Galatians 2:18

For if I build again the things which I destroyed - If I act like a Jew, and enjoin the observance of the law on the Gentiles, which I have repeatedly asserted and proved to be abolished by the death of Christ, then I build up what I destroyed, and thus make myself a transgressor, by not observing the law in that way in which I appear to enjoin the observance of it upon others.