Tertullian

For that must be living after the world, which, as the old man, he declares to be "crucified with Christ," not as a bodily structure, but as moral behaviour.

Besides, if we do not understand it in this sense, it is not our bodily frame which has been transfixed (at all events), nor has our flesh endured the cross of Christ; but the sense is that which he has subjoined, "that the body of sin might be made void, " by an amendment of life, not by a destruction of the substance, as he goes on to say, "that henceforth we should not serve sin; " and that we should believe ourselves to be "dead with Christ," in such a manner as that "we shall also live with Him.