What Is the Sin Nature — Meaning Explained

The doctrine of the sin nature (also called original sin or the flesh) teaches that Adam's fall affected all humanity. Romans 5:12 states, 'by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned.' David acknowledged, 'Behold, I was shapen in iniquity; and in sin did my mother conceive me' (Psalm 51:5). Jeremiah declared the heart 'desperately wicked' (Jeremiah 17:9). Paul described the internal battle: 'the good that I would I do not: but the evil which I would not, that I do' (Romans 7:19). The sin nature is not merely bad habits but a deep corruption that makes humans unable to save themselves. Ephesians 2:1 describes the unregenerate as 'dead in trespasses and sins.' This is why the new birth is necessary (John 3:3) — only God's regenerating power can overcome the sin nature. Through Christ, believers receive a new nature (2 Corinthians 5:17) while still battling the old until glorification.