Tertullian

If, now, he were for excluding circumcision, as the messenger of a new god, why does he say that "in Christ neither circumcision availeth anything, nor uncircumcision? For it was his duty to prefer the rival principle of that which he was abolishing, if he had a mission from the god who was the enemy of circumcision.

Furthermore, since both circumcision and uncircumcision were attributed to the same Deity, both lost their power in Christ, by reason of the excellency of faith-of that faith concerning which it had been written, "And in His name shall the Gentiles trust? " -of that faith "which," he says "worketh by love." By this saying he also shows that the Creator is the source of that grace.