Holiness before God will produce peace with men. That truth we find in Hebrews 12:14 , where we read, "Follow peace with all men, and holiness, without which no man shall see the Lord."
Here is a truth which we must believe. Without holiness we cannot see the Lord. He is holy and has created all things for the glory of His name. Seeing Him is enjoying covenant fellowship with Him. Often, when we say that we are going to see someone, we mean by that much more than simply that we are going to set our eyes upon that person. We mean having fellowship with him. And so it is here. In fact, we cannot see the infinite, everywhere-present God Who is a Spirit. At best we would see only part of Him because of our limitations. The truth is that we will see Christ, Who is God in our flesh.
To have that fellowship with God in Christ we must not fight with other men in order to get a bit more of this world and its riches, which will soon be taken from us through death, and will be changed when Christ returns. If we do not live in peace with our fellow believers, we are not running the race, and we reveal that we have no interest in the prize at the end of that race.
The text above teaches us that undeniable truth that following peace is walking in holiness. It is unholy, that is, sinful, to live in any other way than in peace. Not walking in peace with the brother is breaking God's law, and thus walking in unholiness.
The fact is that not walking in peace means that we are leaving that narrow path on which we must run to end the race and get the prize. Not living in peace is not running the race but seeking things for our flesh. We ought to take hold of the important truth here that not walking in peace is not walking where we will have peace with God, but running away from Him and His covenant fellowship.
Read: Romans 12 .
Herman Hoeksema: "Not creation, not the fall, not the church, not the predestination of the elect, not even the incarnation, not the cross, are first in the good pleasure of God; but the firstborn from the dead, the glorified Christ, is first. He is the firstborn of every creature ..." (Reformed Dogmatics, p. 333).