John Calvin Commentary Hebrews 12:14

"Follow after peace with all men, and the sanctification without which no man shall see the Lord:" — Hebrews 12:14 (ASV)

Follow peace, etc. People are so constituted by nature that they all seem to shun peace, for all pursue their own interests, seek their own ways, and do not care to adapt themselves to the ways of others. Therefore, unless we strenuously labor to follow peace, we will never retain it, because many things will happen daily providing occasion for disagreements. This is the reason why the Apostle urges us to follow peace, as if he had said that it ought not only to be cultivated as far as it is convenient for us, but that we ought to strive with all diligence to keep it among us. And this cannot be done unless we forget many offenses and exercise mutual forbearance.

However, since peace cannot be maintained with the ungodly except by approving of their vices and wickedness, the Apostle immediately adds that holiness is to be pursued together with peace. This is as if he commended peace to us with this qualification: that we must not allow friendship with the wicked to defile or pollute us, for holiness has a special regard for God. Therefore, even if the whole world were roused to a blazing war, holiness must not be forsaken, for it is the bond of our union with God. In short, let us peacefully cherish harmony with people, but only, as the proverb says, as far as conscience allows.

He declares that without holiness no man shall see the Lord; for we will see God with no other eyes than those that have been renewed in His image.