After the Flood destroyed the wicked, God still declared in Genesis 8:21 that the imagination of man's heart is evil from his youth, repeating His verdict of Genesis 6:5. The Flood changed nothing about human character; it only executed judgment and gave the eight survivors a chance to do better. The phrase "from his youth" acknowledges only a narrow window of potential goodness in early childhood. Babies are born morally neutral, able to do good or evil, but because of the flesh they lean toward selfishness and sin, since carnal nature wants everything for itself. Every generation since the Flood shares this same sinful nature, and humanity has not improved, whatever evolutionists claim. Scripture, the story of God's redemption of mankind, bears this out throughout, showing the depths of man's sin alongside the sublimity of His gracious love. David describes human corruption in Psalm 14, and Jeremiah 17:9 declares the heart deceitful above all things and desperately wicked, or incurably sick. Paul gives a complete indictment of mankind in Romans 3:9-18. Sin comes in degrees, and not everyone is a flagrant sinner; many try hard to do good as they understand it. Yet in God's eyes humans grow corrupt from a young age, and just one sin is enough to incur the law's penalty of death. Everyone has committed at least that much, bearing a growing burden of sins throughout life.

God declares His assessment of humanity's moral state just before the Noachian Flood, stating that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually. This stark depiction in Genesis 6:5 contrasts sharply with God's earlier evaluation in Genesis 1:31, where He saw everything He had made as very good. In a relatively short span, humanity degenerated from unspoiled to rotten to the core, illustrating a total depravity that resulted from losing contact with the God of creation. God meticulously observed and scrutinized mankind's behavior over an extended period, watching their steady moral deterioration from purity to wickedness since the expulsion of our first parents from the Garden of Eden. This decline was not a short-term event but a continuous corrosion over centuries until the Flood. God describes this wickedness as great, indicating not just naughtiness but true evil, corruption, and immorality that multiplied exponentially across the earth. This universal condition of sin was pervasive, affecting every region with no area spared from the destruction it brought. Further intensifying this judgment, God notes that every intent of the thoughts of man's heart was only evil continually, emphasizing an internal corruption that drove external violence. Their attitudes sparked wicked thoughts and plans, producing more evil in everything they did. Their hearts contained only evil, with no good remaining, and this evil was ceaseless, constant, and perpetual, dominating their thoughts and deeds from morning until night. This comprehensive depiction underscores a state of total depravity in humanity before the Flood.

Reformed Protestants, often called Calvinists, teach a Doctrine of Total Depravity, which posits that all humanity is sinful, possessing no goodness that can satisfy God. This teaching suggests that while human nature is not completely depraved, it is totally affected by depravity, so that sin taints even the good that people do. Since Adam and Eve ate of the Tree of the Knowledge of Good and Evil, humans have been a mixture of good and evil, but like wine injected with poison, the good in people is corrupted by evil. Even acts of human love and altruism are ultimately driven by selfishness, ego, pride, covetousness, or some other sinful motive. Human nature is indeed marked by corruption and evil, with all having sinned and fallen short of the glory of God. Men and women are sinful and in need of a Savior.

Modern theologians developed the doctrine of total depravity to excuse mankind from any responsibility in the salvation process. They conclude that man is incapable of contributing anything to his own salvation, so concern about obedience becomes unnecessary. The text rejects this claim as unbiblical. While humanity is certainly depraved and capable of great evil, it is not totally depraved. Israel had to walk to the Promised Land and gather manna, actions that symbolized required effort and contribution. Similarly, believers must work out their own salvation, as God ordained good works beforehand for His people to walk in them. Jesus gave unconverted listeners the assignments to ask, seek, and knock, demonstrating that even the unconverted can perform good actions. These commands represent works that must be done to continue receiving God's gifts. If humanity were totally depraved, God would judge everyone incapable of change and send all directly to the lake of fire, yet only a very few fall into that category. Most people simply lack a calling. The doctrine creates an anomaly by urging morality while declaring God's law done away, allowing people to set their own standards and placing them at odds with God's governance.

The doctrine of total depravity holds that the Fall brought mankind into an estate of sin and misery, leaving humanity bereft of original righteousness, corrupt, utterly indisposed and disabled with respect to all spiritual good, wholly inclined to evil continually, and the source from which all actual transgressions proceed. This condition is said to be conveyed to all descendants by natural generation, so that every person is conceived and born in sin. The teaching asserts that every intent of the thoughts of the human heart is only evil continually and that no clean thing can come from an unclean source. It further claims that what is born of the flesh is flesh and that all sinned in Adam, thereby transmitting the guilt and corruption of his transgression automatically through physical descent. The material agrees that the heart is desperately wicked and that all have sinned and fall short of the glory of God, yet maintains that these statements do not establish total depravity. Because the forbidden fruit came from the Tree of the Knowledge of Good and Evil, human nature remains a mixture capable of both good and evil. Even apart from God, Gentiles follow a moral code written in their consciences, refraining from murder, theft, and lying. Jesus Himself acknowledged that evil people nevertheless give good gifts to their children. Across history individuals range across a spectrum from the utterly wicked to the outwardly benevolent, showing that carnal inclination does not eliminate every capacity for good. The cited proof texts are judged insufficient to prove automatic transmission of guilt through blood or genes; they describe the sinful environment into which people are born or the universal tendency to sin, not an inherited stain that renders every person wholly and continually evil from conception. Consequently the doctrine is regarded as overly harsh, portraying humanity as almost irredeemable when Scripture presents a more nuanced condition in which fleshly selfishness inclines people toward evil without extinguishing all moral awareness or the possibility of improvement.

The doctrine of total depravity, as understood within Protestant traditions that trace back to Augustinian thought on original sin, holds that all humanity is sinful and possesses no goodness capable of satisfying God. While not every aspect of human nature is depraved, depravity affects it entirely, so that even the good present in people remains tainted by evil. Since Adam and Eve partook of the tree of the knowledge of good and evil, human beings exist as a mixture of good and evil, yet the good they perform is driven by selfishness, ego, or other sinful motives. The Founding Fathers, shaped by their Protestant backgrounds that included influences from Luther, Calvin, and various forms of Puritanism, held this view or something closely resembling it. Their conviction that human nature is corrupt and therefore easily corruptible directly informed the structure of the republic they established. Because they regarded government as force, control, and power, they separated governmental powers among several entities and instituted checks and balances so that no single person or branch could become strong enough to tyrannize the people. This arrangement reflected their belief that power corrupts and absolute power corrupts absolutely, and it aimed to constrain the effects of human nature within the new nation.

Eliphaz espouses the doctrine of the total depravity of man by asserting that a person born of a woman cannot be pure or righteous at all and that mankind is abominable and filthy, drinking iniquity like water. He reaches this conclusion after meditating on the teachings of a spirit that appeared to him in secret visions by night, a source that denies any possibility of unity between God and man. This teaching holds that God places no trust even in His saints and charges His angels with error, leaving humanity hopelessly separated from the divine with no path to righteousness or atonement. Eliphaz further develops the idea by questioning whether a man can be profitable to God or whether righteousness brings any pleasure to the Almighty, thereby promoting cynicism that rejects the power of God's regeneration and change. Bildad advances the same doctrine by declaring that man is a maggot and a worm, inherently unable to attain purity before God because even the moon and stars fall short of divine holiness. Both men trace their reasoning to ancient fathers who received secret knowledge before the creation of man, a lineage that produces a mixture of truth and lie while denying the gospel promise that humanity, made in God's image, can qualify for His righteousness and join His family. Such contamination of right conclusions with wrong sources from demonic reasoning profanes God's Word and fuels hopelessness rather than the hope drawn from Scripture.