If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us the sins and to cleanse us from all unrighteousness.
Short answer
In the Bible, sin is wrongdoing against God and neighbor: missing the mark God intends, stepping over His commands, and leaving undone the good we know to do. Scripture says everyone sins, and just as plainly that God forgives those who confess.
The short answer
Scripture describes sin as wrongdoing against God and against other people, in thought, word and action. John writes that “sin is lawlessness” (1 John 3:4) and that “all unrighteousness is sin” (1 John 5:17); James adds that whoever “knows to do good and doesn’t do it” sins as well (James 4:17). The Bible says that everyone sins, and it never speaks of sin without also speaking of forgiveness.
The words
The Bible uses several words for sin, and each shows a different side of it.
- Missing the mark. The most common Hebrew verb, chata, and the most common Greek noun, hamartia, both have the basic sense of missing a target or going astray. The Hebrew verb is used of slingers who could sling a stone “at a hair and not miss” (Judges 20:16).
- Transgression. The Hebrew pesha means rebellion or breach of trust; the Greek parabasis means stepping over a line.
- Iniquity. The Hebrew avon suggests something twisted, and also the guilt that follows.
Psalm 51 uses all three Hebrew words in its first two verses:
Have mercy on me, God, according to Your loving kindness.
According to the multitude of Your tender mercies, blot out my transgressions.
Wash me thoroughly from my iniquity.
Cleanse me from my sin.
Where it begins
The serpent said to the woman, “You won’t really die, for God knows that in the day you eat it, your eyes will be opened, and you will be like God, knowing good and evil.” When the woman saw that the tree was good for food, and that it was a delight to the eyes, and that the tree was to be desired to make one wise, she took some of its fruit, and ate. Then she gave some to her husband with her, and he ate it, too.
The story in Genesis 3 presents sin as distrust of God’s word and a grasping at what He had withheld. Its first effects are hiding from God (Genesis 3:8) and blaming others (Genesis 3:12–13). Paul reads the story this way: “sin entered into the world through one man, and death through sin” (Romans 5:12). Jesus locates sin in the heart: evil things “come from within” (Mark 7:20–23).
Christians describe the inheritance of that first sin differently. Catholic teaching speaks of original sin, a condition that wounds human nature without wholly corrupting it. Lutheran and Reformed traditions emphasize a deeper corruption that affects every part of a person. Orthodox Christians often speak of ancestral sin, stressing inherited mortality and weakness rather than inherited guilt.
Everyone
for all have sinned, and fall short of the glory of God; being justified freely by His grace through the redemption that is in Christ Jesus,
If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us the sins and to cleanse us from all unrighteousness.
John writes to believers: denying sin is self-deception, and confession meets God’s faithfulness.
Are some sins more serious?
If anyone sees his brother sinning a sin not leading to death, he shall ask, and God will give him life for those who sin not leading to death. There is sin leading to death. I don’t say that he should make a request concerning this. All unrighteousness is sin, and there is sin not leading to death.
John distinguishes “sin leading to death” from “sin not leading to death,” but he does not say exactly what he means, and interpreters have proposed many answers.
Catholic teaching sees here the scriptural root of its distinction between mortal and venial sin (Catechism of the Catholic Church 1854–1864). A mortal sin is a grave matter committed with full knowledge and deliberate consent; it breaks a person’s friendship with God and is ordinarily forgiven through the sacrament of Reconciliation. Venial sin wounds that friendship without breaking it. Most Protestant traditions do not use this distinction: they teach that every sin deserves God’s judgment and that all sin is forgiven through faith in Christ, while recognizing that some sins do greater harm than others. Jesus’ warning about blasphemy against the Holy Spirit is a separate question: see What is the unforgivable sin?
Forgiveness
When David is confronted, he says, “I have sinned against the LORD,” and is told at once, “The LORD also has put away your sin” (2 Samuel 12:13). Through Isaiah God says, “Though your sins are as scarlet, they shall be as white as snow” (Isaiah 1:18). In Jesus’ parable, the father runs to meet the son who has wasted everything (Luke 15:20). Paul sums it up: in Christ “we have our redemption, the forgiveness of our sins” (Colossians 1:14).
Christians receive that forgiveness in different ways. Catholics and Orthodox confess to a priest in the sacrament of Confession or Reconciliation, pointing to Jesus’ words to the apostles in John 20:22–23. Most Protestants confess directly to God, some also confess to one another (James 5:16), and Lutheran and Anglican churches keep a form of private confession as well. All agree with 1 John 1:9 that God is faithful to forgive.
For more, see Forgiveness and What is grace?