Concupiscence (from Late Latin noun concupiscentia, from the Latin verb , from con-, "with", here an intensifier, + cupi(d)-, "desiring" + -escere, a verb-forming suffix denoting beginning of a process or state) is an ardent, usually sensual, longing. In Catholic theology, concupiscence is seen as a desire of the lower appetite contrary to reason. For Christians, concupiscence is what they understand as the orientation, inclination or innate tendency of human beings to long for fleshly appetites, often associated with a desire to do things which are proscribed.
There are nine occurrences of concupiscence in the Douay-Rheims Bible and three occurrences in the King James Bible. It is also one of the English translations of the Koine Greek epithumia (ἐπιθυμία), which occurs 38 times in the New Testament.
In Judaism, there is an early concept of yetzer hara (Hebrew: יצר הרע for "evil inclination"). This concept is the inclination of humanity at creation to do evil or violate the will of God. The yetzer hara is not the product of original sin as in Christian theology, but the tendency of humanity to misuse the natural survival needs of the physical body. Therefore, the natural need of the body for food becomes gluttony, the command to procreate becomes sexual sin, the demands of the body for rest become sloth, and so on.
In Judaism, the yetzer hara is a natural part of God's creation, which God provides guidelines and commands to help us master this tendency. This doctrine was clarified in the Sifre around 200-350 CE. In Jewish doctrine, it is possible for humanity to overcome the yetzer hara. Therefore, for the Jewish mindset, it is possible for humanity to choose good over evil, and it is the person's duty to choose good [see: Sifrei on Deuteronomy, P. Ekev 45, Kidd. 30b].
Augustine of Hippo believed that Adam and Eve's disobedience was the result of a foolish act of pride. Because of this prideful act, Adam and Eve acquired concupiscence which was a wounding of their perfect nature. Concupiscence was not sin in itself, but a deprivation of good, or a wounding of the ability to choose good and resist evil. Augustine believed that baptism healed this wound and grace keeps this wound called concupiscence sealed.