What is the ‘sin nature’?
Question 6006
Why do we sin? Is it simply a matter of bad choices, poor upbringing, or environmental factors? Or is there something deeper, something fundamentally wrong with us at the core? The doctrine of the sin nature, sometimes called original sin or inherited depravity, addresses this question. It teaches that every human being is born with an inward inclination toward sin, a corruption of our nature inherited from Adam that makes sinning inevitable and holiness impossible apart from God’s grace.
The Biblical Evidence
David wrote, “Behold, I was brought forth in iniquity, and in sin did my mother conceive me” (Psalm 51:5). This is not a comment about his mother’s morality but about his own condition from the very beginning of his existence. David was a sinner from conception, not because of anything he had done but because of who he was by nature.
Paul makes this even clearer in Ephesians 2:3: “Among whom we all once lived in the passions of our flesh, carrying out the desires of the body and the mind, and were by nature children of wrath, like the rest of mankind.” Notice that phrase: “by nature.” Our problem is not merely what we do but what we are. We are sinners by nature, and that nature expresses itself inevitably in sinful thoughts, words, and actions.
In Romans 5:12-19, Paul explains how this came about. Through Adam’s sin, sin entered the world, and death through sin. Because of one man’s disobedience, the many were made sinners. We inherit Adam’s guilt and Adam’s corruption. We are born with a nature that is inclined toward evil, hostile to God, and unable to please Him.
What the Sin Nature Affects
The sin nature corrupts every part of us. Theologians sometimes call this “total depravity,” though the term can be misleading. It does not mean we are as bad as we could possibly be or that we can do nothing that appears good by human standards. It means that every aspect of our being, mind, will, emotions, body, has been affected by sin. There is no part of us that remains untouched.
Our minds are darkened: “The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned” (1 Corinthians 2:14). Our hearts are corrupt: “The heart is deceitful above all things, and desperately sick; who can understand it?” (Jeremiah 17:9). Our wills are enslaved: “Everyone who practices sin is a slave to sin” (John 8:34).
This is why Paul’s diagnosis in Romans 3 is so comprehensive: “None is righteous, no, not one; no one understands; no one seeks for God. All have turned aside; together they have become worthless; no one does good, not even one” (Romans 3:10-12). The picture is bleak because our condition is bleak.
The Sin Nature and Human Responsibility
Some object that if we are born with a sin nature, it is not fair for God to hold us responsible for our sins. We cannot help being what we are. But Scripture holds together both our inherited corruption and our personal responsibility. We sin because of our nature, yes, but we also sin willingly. No one forces us to sin. We do what we want to do, and what we want to do is sinful because our wants are corrupted.
Jesus explained this: “For from within, out of the heart of man, come evil thoughts, sexual immorality, theft, murder, adultery, coveting, wickedness, deceit, sensuality, envy, slander, pride, foolishness. All these evil things come from within, and they defile a person” (Mark 7:21-23). Our sins flow from our hearts, and our hearts are corrupt. We are guilty not despite our nature but because of it, for our nature is itself a consequence of Adam’s guilt that we share.
The Solution to the Sin Nature
This is why we need new birth. Cleaning up our behaviour will not solve the problem because the problem is not primarily behavioural. We need new hearts, new natures, new life. And that is precisely what God promises in the new covenant: “I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh” (Ezekiel 36:26).
In Christ, we are new creations. The old has passed away; the new has come (2 Corinthians 5:17). The believer receives a new nature, though the old nature continues to be present and active until glorification. This is why Paul speaks of the ongoing battle between the flesh and the Spirit (Galatians 5:17). We are no longer slaves to sin, but the sin nature has not yet been eradicated. It will be, when Christ returns and we are fully conformed to His image. Until then, we fight by the power of the Spirit, looking forward to the day when the struggle will be over and we will be sinless at last.
“And you were dead in the trespasses and sins in which you once walked… and were by nature children of wrath, like the rest of mankind.” Ephesians 2:1-3