Whatever differs from the norm of the law is sin: but concupiscence in the regenerate differs from the norm of the law. Therefore.

Moral corruption fighting against the law, for the crucifying and mortifying of which Christ himself died on the cross, if it be not properly sin, then Scripture has not explained to us what the property of any habitual sin is.

The Apostle himself in Rom. 6 & 7 shows quite openly that concupiscence is sin properly so called: for not only does he often call it sin, but not good, evil, to be held in hatred, fighting against the law of God, to be crucified, mortified, and destroyed, and rendering that man miserable in whom it resides.

This corruption of nature is here forbidden, for it is truly and properly sin, Rom. 6:12 and 7:17. It is the flesh that lusteth against the Spirit, Gal. 5:18; and if sin, it must be contrary to and forbidden by the law.

He, then, who admits not that all the desires of the flesh are sins, and that that disease of concupiscence, which they call a stimulus, is a fountain of sin, must of necessity deny that the transgression of the law is sin.