Reading Sermons

Purging Out the Old Leaven


(This can be used as a Preparatory Sermon)

Scripture Reading: I Corinthians 5

Psalter Numbers:






            You probably know, beloved, that there were seven Old Testament feasts that the Israelites were commanded to keep.  But what would you think if I told you that the command to keep those Old Testament feasts was still in effect – that you were still required to keep those feasts today? That is what the Word of God tells us here in I Corinthians 5:7, 8. When the Word says, "Therefore let us keep the feast," it's talking about one if those Old Testament feasts and telling us as New Testament Christians that  we too must keep that feast!

            There's a sense, you see, in which nothing of the Old Testament has passed away.   In some respects the Old Testament is over and done with, but there is another sense in which nothing has passed away. The Belgic Confession reminds us of that in Article 25: “We believe that the ceremonies and figures of the law ceased at the coming of Christ, and that all the shadows are accomplished, so that the use of them must be abolished amongst Christians; yet the truth and substance of them remain with us in Jesus Christ, in whom they have their completion.” In its typical and shadowy form the feast referred to In I Corinthians 5:7, 8 has passed away, but its truth and substance still remain with us in Christ. For that reason we are commanded to keep that feast in its spiritual reality.

            In the context Paul is talking about discipline in the church and the necessity of discipline. It's in that connection that we read in verse 6. "A little leaven, leaveneth the whole lump." Sin must be put out of the church through discipline, otherwise it works in the church like leaven, and the whole church is corrupted by sin. And so Paul says, "Make that sin is dealt with in the church through church discipline, lest you all be corrupted by the presence of that sin – lest your whole fellowship and all of your work be affected by it. Put out from among you,” he says, “that wicked person, the person who does not repent of his sins.”

            But then he goes on and speaks of discipline in a more personal way. Discipline is necessary in the church and must be carried out in the church, but there's a certain kind of discipline for which we are all responsible. If we are busy with that kind of discipline there never will be any need in the church for formal discipline by the elders. Paul is talking about that personal obligation and responsibility, what we might call personal discipline, in verses 7 and 8, when he says, “Purge out therefore the old leaven, that ye may be a new lump.”

            When we do that – when we purge out the old leaven of sin, then we are in fact keeping the feast as our text commands, keeping it not as the Israelites did, in its old shadowy form. but keeping it in its New Testament spiritual reality – keeping it as New Testament Christians.

            So I call your attention this evening to those verses with the theme:


... and to three things in that connection.  First we need to look briefly at the Old Testament Feast and see what it was all about.  It is the picture of and pattern for the feast that we are commanded to keep. Then we need to look at the New Testament fulfilment of that feast, and finally at the abiding reasons the Word of God gives for keeping the feast.  Those reason for keeping the feast are two: “Ye are unleavened,” and “Christ our passover is sacrificed for us.  You will never find any better reason than those for keeping this feast.


            Let us notice, then, that the feast which Paul is talking about here is not the Passover.  He speaks of the Passover, but that's not the feast he's telling us to keep.  He's talking here about a feast that began the day after the Passover.  You probably know that the feasts were celebrated in groups. In the Old Testament you didn't have to go seven times to Jerusalem to keep the seven feasts.  You only had to go three times.  And that was because you could keep several of these feasts at the same time.  You have an example of that here.  The feast Paul is talking about began the day after the Passover.  So those who had come for the Passover would stay this feast as well, and so fulfill their obligations as God's covenant people.

            Even in the New Testament this feast to which Paul is referring follows the Passover.  When he says, “Even Christ our passover is sacrificed for us,” then he means that for us too the true passover is finished and this feast has begun.

            The feast that Paul is referring to is the Old Testament feast of unleavened bread.  We read of that feast in Exodus 12. I think it would be of some profit to read a few verses from that chapter.  There are some things well worth noticing in Exodus 12:18-20, the verses that describe this feast.  There we read: "In the first month, on the fourteenth day of the month at even, ye shall eat unleavened bread, until the one and twentieth day of the month at even."

            We learn from Exodus 12 that this feast lasted for seven days and was a feast in which the Israelites had to do completely without leaven: "Seven days shall there be no leaven found in your houses: for whosoever eateth that which is leavened, even that soul shall be cut off from the congregation of Israel, whether he be a stranger or born in the land.  Ye shall eat nothing leavened; in all your habitations shall ye eat unleavened bread."

            Since few of our mothers and wives bake their own bread any more, we should understand that leaven is the same as yeast.  You put leaven into bread dough to make the bread rise and become soft and light when it is baked.  If you don’t put leaven in then you get unleavened bread which is something like a thick hard soda cracker.  That was what the Israelites ate during this feast.

            The feast of unleavened bread was a commemoration of Israel's deliverance from Egypt.  Israel had eaten unleavened bread the night that they left Egypt, at the first Passover.  They remembered what had happened to them at that time by eating nothing but unleavened bread for a week during this feast of unleavened bread.  During that feast they were not even allowed to have yeast in their houses.  For a whole week they had to do without it.

            There is an old Jewish tradition which says that on the first day of the feast the father, or the head of the house, would search the house with a candle and would make sure in a kind of ritual fashion that there was in fact no yeast in the house – no leaven.  There is a reference to that practice in the prophesy of Zephaniah.  In Zephaniah chapter 1:12 God says, that just as the head of the household would search his home for yeast on the first day of the feast, so God would search Jerusalem with a candle.  “It shall come to pass at that time that I will search Jerusalem with candles, and punish the men that are settled on their lees: that say in their heart, The Lord will not do good, neither will he do evil.”  He would punish them by throwing them out of His Jerusalem just as the Jews threw all their yeast out of the house on the first day of the feast of unleavened bread.

            But the question that we need to answer is, Why did they have to get rid of their yeast, their leaven for the week of this feast?  Why was that so important?  Why were they not even allowed to have leaven in the house during this feast?  And why were they threatened with excommunication from the nation of Israel if they were found with yeast during this time?  Do you know the answer to those questions?

            The answer lies in the Biblical symbolism of yeast or leaven.  When you think of yeast, you must think of something that has the power to work its way into and through something else.  Anyone who has baked bread knows what yeast does.  When you put yeast in dough then the yeast works all through the dough and affects the whole lump of dough so that the dough rises and you can bake a nice loaf of bread with it.  That power to work all through something and affect it is what Scripture is emphasizing whenever it speaks of yeast.

            Sometimes in Scripture, good things that have that power are compared to yeast.  In Matthew 13 Jesus compares the kingdom of Heaven to yeast which a woman hides in some dough. Jesus compares the kingdom of heaven to yeast or leaven because it has that power to work in and through all of our lives and affect our whole life.  When God by His grace establishes His kingdom in your heart, then the kingdom doesn't remain in your heart, but it works through into every area of your life.  Then your speech becomes the speech of the kingdom; your conduct becomes kingdom conduct.  Then you become in everything a citizen of that kingdom of heaven.  You become a citizen of the kingdom in heart and mind and soul and strength.  From that point of view the kingdom of heaven is like yeast, or leaven.

            But there are sometimes bad things that are compared to yeast as well.  They too are compared to yeast because they have that same power to get into something and to work in it and through it until the whole is corrupted and filled with that bad thing.  The doctrine of the Scribes and Pharisees is compared to yeast in Matthew 16:6, because their doctrine was not just wrong but would work through and corrupt all the life of God’s people.

            Most often, though, when Scripture compares something to yeast, it compares sin to yeast or leaven.  Sin has the power to work through everything and corrupt everything.  That's something that we may never forget.  We very often sin against God, and it seems that sin isn't really a very big thing, but neither is yeast.

            If you know anything about sin, then you know that sin is like yeast.  Even you children know that.  When you tell a lie then that is not the end of the matter.  One lie leads to another lie, and then another.  That's one of the ways in which sin is like leaven.  Sin grows.  It grows and spreads just like yeast in dough.  It works it's way into your whole life until your life is completely corrupted by sin. What began as a little sin ends with a man leaving the church, abandoning the faith, going his own way.  That's sin working like leaven.  That's one of the things that the Apostle Paul is bringing to our attention here in these verses.

            For that reason sin must be put away.  In the same way that the Israelites had to search every corner of the house and make sure that there was no leaven in the house, it is our great business as believers to do the same with respect to sin.  We must be busy always, not just once a year, not just four times a year when the Lord's Supper is celebrated, but always – busy purging out the leaven of sin.

            When we do that, then we’re keeping the feast – keeping the feast of unleavened bread.  We’re are not keeping it in that typical way that the Jews kept it in the Old Testament.  That was, after all, just a picture.  But we’re keeping the spiritual reality to which that Old Testament picture pointed.  You are keeping the real feast of unleavened bread, not the picture feast, when you are busy purging out the leaven of sin.

            Remember, too, that the keeping of that feast, as Paul points out in the context here, is necessary.  The church will be destroyed if we don't keep the feast. Just as Israel was destroyed as a nation because it would not keep the feasts of Jehovah, so will we be destroyed.  Not only does a little leaven leaven the whole lump, but the presence of the leaven of sin in the church brings down the judgment of God on the church.


            All that does not explain, however, how we keep the feast.  Do you know what that involves?

            We keep this feast, first of all, through self-examination.  Self-examination corresponds to that Old Testament ritual of searching the house.  In self-examination you search not a house made with hands, but you search your own spiritual house – yourself.  You search it from top to bottom, from basement to attic.  You search every dark corner and every room – heart, soul, mind, motives, deeds. You search them all in order that the leaven of sin may be put away.  Practicing self-examination is keeping the feast.

            That important work of self-examination, though we always emphasize it in connection with the Lord's Supper, is the daily calling of the people of God.  You are not just called to self examination four times a year, but every day.

            We also keep the feast when we repent of our sins.  That corresponds to the Israelites’ putting their yeast out of the house.  It's hard to explain to someone who does not know anything about repentance, but repentance is in fact a purging and putting out of sin.  It is that because when you repent of your sin you are saying before the face of God that you want nothing more to do with sin – you don't ever again want to have anything to do with it.

            But repentance is also a putting out of sin in that it clears the conscience and the heart before God.  You know that if you have ever truly repented of sin – that repentance really does, by the grace of God, take away the sin that you've committed.  It's like an enormous burden being lifted away.

            In I John 1, John talks about that. if we confess our sins, John says, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.  In the way of repentance we experience and enjoy relief from the burden of guilt and sin.

            Conversion, too, is also part of keeping this feast.  Conversion means, very simply, that you turn from your sin and pray for grace to be holy.  That's part of keeping the feast, and is like the Israelite closing the door after throwing out the leaven and making sure that the leaven was not brought back into the house.

            Keeping the New Testament feast of unleavened bread is not easy.  It was an easy thing to keep the Old Testament feast.  All you had to do was get rid of whatever yeast you had in the house.  That wasn’t hard to do.  Purging out the leaven of sin is another matter altogether.  That requires some effort.  In fact, you can’t do it yourself.  You need first of all the candle of the Word of God.  Only it can shed its light in the dark corners of your life and discover the sins that lurk there.  Only that candle of the Word can discover our sinful nature as the source of every evil deed and thought.

            In Corinthians Paul talks about that. I Corinthians 11:31 says: "If we would judge ourselves, we would not be judged."  Only the Word has the power to show us our sinfulness and convict us of sin.  You should know that from your years of sitting under the preaching of the gospel.  It does indeed have a way of shining into those dark corners.  Sometimes the minister preaches the sermon and doesn’t even realize that by the candle of the Word which he holds up, those dark corners of your heart are being lightened, and the sins that are hidden in those dark corners found out.  That's why the Word sometimes leaves us uncomfortable, even angry.  But that's the way it must be, and you know that too.  You will need the Word of God, therefore, in order to fulfill your calling to keep the feast.

            You will also need the work of the Spirit of God.  Only the Spirit can give you strength to repent of sin and hate it and put it away.  You will never do that yourself.  Anyone who has resolved over and over again to do what is right and failed knows that from bitter experience.

            In speaking of these things, Paul warns us against some dangers.  He doesn't just say, “Purge out the old leaven.  Get rid of the sin.  Repent of it.  Practice self examination, repent and be converted.”  But he mentions specific sins, “malice and wickedness.”  There are of course, I suppose, innumerable sins that could be mentioned.  But he mentions just malice and wickedness.  There must be a reason for that.  Why?

            He mentions malice exactly because it is a specific sin.  There is the danger in repentance and in self examination that we never get around to dealing with specific sins. Almost always when we pray we ask for forgiveness.  We say, “Forgive me and forgive my family their sins.”  But we fail completely to confess any specific sins that we've committed.  Angry, harsh, uncharitable words, malice, whatever the case may be, we seem never to get around to confessing them.

            That can even be a way in which we hide our sins.  While we convince ourselves that we are in fact busy with repenting, there's not a single specific sin that we've actually committed that we've ever faced up to, confessed as sin, and repented of before the face of God.  We have to watch out for that. And that's one of the reasons why Paul takes the time to mention specific sins here.

            Another reason why he mentions the sin of malice, is that it's a very common sin ands a sin that works just like leaven.  It’s like leaven first of all because you never really see it.  It's hidden way down in the dark corners of my heart or of yours.  But it eats there, and it grows there and it spreads there until it's corrupted the whole of my spiritual life, or of yours.  The book of Hebrews talks about that when it talks about bitterness.  It says, “Be sure that you put bitterness away, because if you let it stay there, then it will grow. It will put down roots.”  That a little different figure but the same idea. Bitterness, like malice will put down roots and grow in your heart until it destroys you.

            So Paul is saying to us, when he mentions malice, “Make sure in this business of putting out the old leaven of sin that you really do it.  Don't just make a pretense of it.  Be sure that you acknowledge and deal with and put away the actual sins of which you are guilty.  Very often those are exactly those sins that you're inclined to love and to cherish and to keep.

            Paul also mentions, or uses the word “wickedness” here.  That's not so much a reference to a specific sin but a word that we can use to describe all sin.  He uses that word for another reason, to remind us that the leaven of sin is rooted in and has its source in our old nature.  Putting away sin is not just being sorry for some things that I've done, although it includes that too.  But it's coming by the grace of God, to the realization that Iam a sinner and that those sins that I commit have their source in the filthy fountain of my own nature.  That too has to be acknowledged and repented of.

            How often are you sorry for what you are?  How often do you confess to God the fact that you are corrupt and depraved – not just that you've done evil.  If you don’t, I suggest that you really do not know the reality and power of sin in your own life.  You and I do not really understand sin until we understand and face up to the depravity of our natures.

            By speaking of wickedness, therefore, and reminding us that sin is embedded in our very nature, Paul is simply saying that we can never, ever win this battle, and do this work, and keep the feast, by our own efforts.  Keeping the feast is not just a matter of having the Word then, but a matter of depending utterly and wholly upon the sovereign grace of God in Christ Jesus.  Only grace can lead me to honest self-examination. Only grace can produce the tears of repentance.  Only grace can bring conversion.

            So there's a warning implied too: Keep the feast in sincerity and truth.  Be sure you keep it.  It was possible in the Old Testament to make some sort of a pretense of keeping the feast, by going to Jerusalem and abstaining from yeast during the week of the feast, but doing it only as a traditional thing.  That was an abomination to God – as much as if you never came to Jerusalem. Paul is saying, “Be careful that you do in fact keep it. It's not just a pretense.  That you don't just say the right words, ‘Forgive us our sins.’  But that you in fact, are busy with this work of purging out the leaven.”

            Sincerity and truth are compared in our text to the unleavened bread the Israelites did eat during the feast.  Keep the feast, Paul says, “with the unleavened bread of sincerity and truth.”

            The Israelites were not only commanded to put away the leaven, but also to eat unleavened bread.  That was an important part of keeping the feast.  Putting away the leaven was the negative part of the feast.  Eating the unleavened bread was the positive part of keeping the feast.

            We have that same two-part calling.  We must put away the leaven of sin, but we must also eat unleavened bread.  In fact, we put away the leaven of sin for the sake of keeping the feast with unleavened bread.

            Eating the unleavened bread of sincerity and truth is for us the same things as living a life of Christian gratitude and obedience to God.  That's what matters.  And the purpose of putting away the leaven of sin is that we may do that with all our heart, and mind, soul and strength.

            Even in that, however, there's a warning.  The warning is against the person who thinks he’s keeping the feast only because he’s dealt with a specific sin.  An example is the man who thinks he's converted because he's put away the sin of drunkenness.  That's not conversion, not all by itself.  A man who is truly converted from drunkenness, or whatever sin, lying, stealing, whatever, is only converted when in the place of that drunkenness there is a real thirst after the living God.  Only when the filthy life of the adulterer is replaced by the purity of holy obedience in marriage and in the single life is a man or a woman truly repentant and truly converted.  Only then is he or shee keeping the feast with the unleaved bread of sincerity and truth.

            And that's why Paul says that the feast must be kept with the unleavened bread of sincerity and truth.  He uses those two words to remind us of the fact that from that positive point of view there are two things that characterize the holy obedience of the child of God.  As he puts away sin and strives to live in holy obedience to God, there are two things that characterize him.  The one is sincerity.  Not hypocrisy, not a mere show of obedience, but sincerity of heart.  And with that, comes truth.  Our holines, our obedience, must be according to the Word of God.

            We can use the Old Testament example to illustrate what God is saying here.  You couldn't keep the feasts in the Old Testament, not really, if you didn't come to those feasts with all your heart, remembering and being thankful for what God had done for His people in bringing them out of bondage and to the promised land.  That's why God says in Isaiah that those Jews who brought their sacrifices, but didn't bring them from a heart that was true and right with God, might just as well have been cutting off pig's heads, or killing or murdering their neighbors, as bringing lambs.  It really wasn't any different if it was without sincerity.

            But they weren't keeping the feast either if they came and did as they pleased.  Keeping the feast meant doing exactly as God commanded and doing all that He required.  The feast must be kept also in truth.


            Laying that calling before us, Paul gives us two reasons for obedience.  Those two reasons are God's work in us and God’s work for us.  God’s work in us is described with the words, “For ye are unleavened.” God’s work for us is described with the words “For even Christ our passover is sacrificed for us.”  Two better reasons for keeping the feast you will not find.

            The Word of God here, therefore, appeals first to God’s great work of grace in us – the work that He does by His Spirit and Word in regeneration, calling, faith, conversion, and all of the rest.  The result of that work is that we are unleavened, that is, without sin, at least in principle.

            Scripture never just says, “Do it.’  Or, “Don't do it.”  Scripture, when it brings it's commands, always goes back to the work of God.  You hear those commands of Scripture.  You look at yourself, and you say, “How can I?”  And you try and you fail and you feel like giving up.  Scripture doesn't just say then, “Well you've got to go on anyway – you have to do it anyway.”  But Scripture goes back to that work of grace and says, “Remember – remember what God has done.”  And then the Christian says, “Yes, God has begun in me His work of grace.  It hasn't gone on very far yet.  It's only a beginning.  But God has begun it.  And therefore, though I'm discouraged, though my sins rise against me, I know that I can go on.  And I know that I will go on.  I know that I must go on.”

            And when the Christian is reminded of the fact that in principle, by the grace of God in Jesus Christ, he is unleavened, a new man in Christ, created not by his own efforts, but by the almighty power of the Spirit of God, then he says, “Yes.  Yes.  This is what I must do.  This is what I will do, God helping me.”

            In the second place, Paul appeals to God's work for us.  We must do this, we will do this, also because Christ died for us: “Even Christ our passover is sacrificed for us.”

            When he calls Christ our passover he is speaking of Christ as the Lamb of the Passover, the lamb without spot or blemish that was offered to God as a sacrifice for our sins.

            That sacrifice of Christ offered once for all is an encouragement to the believer in his calling to keep the feast of unleavened bread.  The Lamb has been slain as an atonement for those very sins against which he struggles.  What greater encouragement could there be for that, than to know that these very sins which rise up against me, and which so discourage me by their presence always, are already paid for by the death of that Lamb.

            By His sacrifice, Christ has purchased everything you are fighting for, waiting for, struggling for, repenting for.  It's all purchased already.  He’s purchased for you the right to keep the feast, the power to keep it, and every good thing you do in keeping it.  The keeping of the feast is yours by His blood and righteousness.

            How shall I be holy?  How shall I overcome in this battle?  How shall I keep the feast?  All I see is the struggle and the end of that struggle does not appear very clear to me.  But I know this, that the victory is won, the blessings purchased, all accomplished by the death of Christ.  And so too I am willing and do keep the feast as the Word of God commands through Him who is my all.

            The passover, you see, is finished.  The Lamb is slain, the blood sprinkled, atonement made, all things purchased for us by the priceless blood of Christ.  That's all done.  We're not called to keep that feast. Christ kept it in His suffering and death.  Now it’s the day after the passover, the first day of the feast of unleavened bread, a feast which will last until Christ returns.  Of that rest the Word of God says, “Keep it. Keep it. Don't stay away.  Don't be a hypocrite in coming.  Keep the feast; not with the old leaven, neither the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth.”  Keep it in self-examination, in repentance, in conversion and in sincere and thankful obedience to God until He comes again.

            And lest we forget or become slothful let us remember the warning of Exodus 12: “Keep the feast, lest you be cut off.”


Hanko, Ronald

Rev. Ronald Hanko (Wife: Nancy)

Ordained: November 1979

Pastorates: Wyckoff, NJ - 1979; Trinity, Houston, TX - 1986; Missionary to N.Ireland - 1993; Lynden, WA - 2002


Contact Details

  • Address
    317 North Park St.
  • City
  • State or Province
  • Zip Code
  • Country
    United States
  • Telephone
back to top

Contact Details


  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • Reading Sermon Library
  • Taped Sermon Library

Synodical Officers

  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.

Synodical Committees

  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • Emeritus Committee
  • This email address is being protected from spambots. You need JavaScript enabled to view it. 
  • This email address is being protected from spambots. You need JavaScript enabled to view it.


  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.
  • This email address is being protected from spambots. You need JavaScript enabled to view it.

Classical Officers

Classis East
This email address is being protected from spambots. You need JavaScript enabled to view it.
This email address is being protected from spambots. You need JavaScript enabled to view it.

Classis West
This email address is being protected from spambots. You need JavaScript enabled to view it.
This email address is being protected from spambots. You need JavaScript enabled to view it.