What a tremendous change was wrought in Paul's life! He was a fierce enemy of Christ and His church, agreeing fully with those who stoned Stephen, that faithful servant of Christ. But being converted by God's grace he became willing to suffer persecution for believing in Christ, Who worked an amazing change in him.
And now, instead of boasting about what he did after his conversion, he tells the Philippians in Philippians 3:3, 4 that he no longer has confidence because of what he was and did, but rather rejoices in what Christ did for him. He wrote, "For we ... rejoice in Christ and have no confidence in the flesh, though I might also have confidence in the flesh."
As an unbeliever he would boast of what his flesh did. Now he tells us what the confidence of a child of God is. He had been highly respected as a Pharisee by other enemies of Christ; and he was considered as one surely entering into heavenly glory when he died. But now his confidence is in what Christ did, not in what he was and did.
But stand now before the mirror of God's Word. Do you see your works as that which gives you confidence and assurance that you are a child of God? Does even the faith God gave you look to you as that which you deserved because of what you did? Do you boast of having opened your heart and let Christ come in? Or humbly can you confess that this is a free gift of God which you do not of yourself deserve?
Let Paul's words warn you. Let him be your example when he writes that he rejoices in Christ Jesus. We must find faith and good works in our lives, or we can have no confidence of being children of God. But we must see that faith and those good works as God's gift to us and not ours to Him. With the psalmist we must sing, "All that I am I owe to Thee, Thy wisdom Lord hath fashioned me; I give my Maker thankful praise, Whose wondrous works my soul amaze."
Read: Romans 9:1-16 .
"One great reason of the carnal security into which we fall, is our not considering how singularly we were fashioned at first by our Divine Maker." John Calvin