In his Confessions, Augustine (354-430) describes mankind’s universal sinful bent as “concupiscence.” The Greek word epithumia (ἐπιθυμία) occurs 38 times in the New Testament. It describes the utter enfeebling of mankind’s freedom of will through the bondage of sin. It is the fallen nature’s inclination to wickedness, desire for immorality, and passion for iniquity, that results in the whole human race becoming what Augustine called a Massa Damnata, a mass of perdition.
Concupiscence is the privation of good, the very real and substantial moral wound that inhibits us from choosing that which is right and good and true. Augustine's view of universal concupiscence, often called “Philosophical Realism,” is the basis for his understanding “original sin.” This is the doctrine that declares all of humanity was really and tangibly present in Adam, our federal head, when he sinned, and therefore all of us are native born sinners. Original sin, according to Augustine, consists of the guilt of Adam, which all humans inherit.
The main theological opposition to the doctrine of concupiscence came from the British monk Pelagius (354–420). Although none of his writings have survived, the eight canons of the Council of Carthage in 418 provided an apologetic answer to his errors. Pelagianism insisted that mankind has the innate ability to choose good over evil, thus rejecting the idea of concupiscence, and embracing a concept similar to the Talmudic concept of Yetzer Hara—a free will option for a graceless estate of good.
Chapter Six of the Westminster Confession of Faith states that original sin is “original corruption, whereby we are...inclined to all evil, do proceed all actual transgressions...” and that corruption as well as the act "are truly and properly sin.” This means the desires to sin themselves are properly understood as sin. It is a sin to be tempted to sin, when that phrase is understood to mean an internal temptation of desire towards that which is a violation of God's law. Concupiscence is sinfulness.
This is really nothing more than the Apostle Paul’s doctrine of “the flesh,” (Romans 7, Ephesians 2, Galatians 5). Paul makes it plain that there is clearly no option for us to unite a fallen identity with a Christian one (Romans 6:1-23; Ephesians 4:22-24). Indeed, when Paul described the estate of the Corinthian Christians before and after conversion, he made it clear: old sin identities, not just old sin practices, had necessarily been left behind because of the work of redemption:
“Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, nor thieves, nor the covetous, nor drunkards, nor revilers, nor swindlers, will inherit the kingdom of God. Such were some of you; but you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus Christ and in the Spirit of our God” (1 Corinthians 6:9-11).
Notice the emphatic language: “Such were some of you.” Past tense. No longer the case. The Corinthian believers had “put off the old man” (Ephesians 4:22). “Therefore, if anyone is in Christ, he is a new creation. The old has passed away; behold, the new has come” (2 Corinthians 5:17). We are not what we once were. We are not defined by what we once did. Our identity is “in Christ” (John 1:12; Romans 6:6; Ephesians 1:5; 1 Peter 2:9).
We see the same truth in the way James describes the temptations of internal lust (James 1). It is what Jeremiah describes as the depravity of the human heart (Jeremiah 17). When Jesus declares that the sin of adultery is committed not only by some outward act, but in our heart and with our eyes (Matthew 5:28), He too is describing concupiscence. In other words our sinful desires, and not just our sinful acts, call for full and complete repentance. There are to be no halfway measures. We are called in the Gospel to “mortify the flesh” (Colossians 3:5-25; Romans 8:13-15).
Matthew Henry, commenting on James 1:14-15, wrote, “As holiness consists of two parts: forsaking that which is evil, and cleaving to that which is good, so these two things, reversed, are the two parts of sin. The heart is carried from that which is good, and enticed to cleave to that which is evil. It is first by corrupt inclinations, or by lusting after and coveting some sensual or worldly thing, estranged from the life of God, and then by degrees fixed in a course of sin.”
Here is the bottom line: the raging debates over gender and sexuality issues in our day all too often miss the essential point. While gender and sexuality are indeed important issues, there is an issue far more important, one that serves as the foundation underlying all these ancillary matters, and that is the issue of the Gospel itself. What we are witnessing is a revival of the ancient battle between Biblical, Augustinian orthodoxy and Unbiblical, Pelagian heterodoxy.
As G.K. Chesterton once quipped,
"Unless a man become the enemy of evil, he will not even become its slave but rather its champion. God Himself will not help us to ignore evil, but only to defy and defeat it."
Or, as Thomas Chalmers sagely observed,
"There is naught more undeniable than the antipathy of fallen nature to the peculiar doctrines of the Gospel."