18. For if I build again. The reply consists of two parts. This is the first part, and informs us that the supposition now made is at variance with his whole doctrine, since he had preached the faith of Christ in such a manner as to connect with it the ruin and destruction of sin. For, as we are taught by John, that Christ came not to build up the kingdom of sin, but “that he might destroy the works of the devil,” (1 John 3:8,) so Paul declares, that, in preaching the gospel, he had restoreth true righteousness, in order that sin might be destroyed. It was, therefore, in the highest degree improbable, that the same person who destroyed sin should renew its power; and, by stating the absurdity, he repels the calumny.