Christian Heritage - July 7 - We Sin by Consenting

"The law is good because it forbids what ought to be forbidden and commands what ought to be commanded. But when people imagine that they can fulfill the law by their own strength without the grace of their Savior, this presumption proves useless, and in fact even harms them, for they are then seized by a stronger desire to sin, and through their sins they also become transgressors. For where there is no law, neither is there transgression.

"Therefore, let the prostrate sinner, knowing that he cannot rise by his own strength, implore the aid of the Savior. Then he will be given grace which will forgive past sins, assist his own efforts, bestow a love of righteousness, and take away fear. Even after this happens, various desires of the flesh will continue to battle against our spirit as long as we are in this present life, and will try to lead it into sin, but the spirit, firmly established in the grace and love of God, will resist these desires and cease to sin. For we sin not by having evil desires, but by consenting to them."

Augustine of Hippo (AD 354-430), Expostio ... ex Epis. ad Rom. 13-18: PL 35, 2065-2066

This is a classic expression of traditional (and Augustinian) Christian antrhopology. Concupiscentia remains even after regneration enables the will to resist concupiscent desires by grace.