Can God sin?

from the old testament

• Sin, by definition, is a lack of holiness. God is, by nature, holy, so it's impossible for Him to sin (Leviticus 19:2; Isaiah 6:3).
• This means that “there is no unrighteousness in him (Psalm 92:15b) and that He is “without iniquity” (Deuteronomy 32:4b). Indeed, “far be it from God that he should do wickedness” (Job 34:10).
• Because God is holy, He doesn’t lie (Numbers 23:19), doesn’t change His mind (repenting for an error, 1 Samuel 15:29), nor even have sinful thoughts (Jeremiah 7:31). In other words, God cannot sin because He cannot do anything contrary to His holy nature.
• The prophet Habakkuk says that God "cannot look at wrong" (1:13). This does not mean that He is not aware or incapable of understanding our sin but that He cannot tolerate nor approve of sin (Habakkuk 1:13) because He is holy.
• The psalmist says of God, "there is no unrighteousness in him" (Psalm 92:15). In short, “The LORD is righteous in all his ways” (Psalm 145:17a).

from the new testament

• Scripture associates darkness with sin. John described God’s nature when he said that “God is light, and in him is no darkness at all” (1 John 1:5).
• James said, “God cannot be tempted with evil” (James 1:13c) because His nature is not subject to corruption. Theologians refer to this as His impeccability. This is why He “cannot lie” (Titus 1:2; cf. Hebrews 6:18) and “cannot deny himself” by being unfaithful (2 Timothy 2:13).
• Jesus, being fully God, is also impeccable. Being fully man, He lived like us but without sinning (Hebrews 4:15; 7:26). In Jesus we perfectly see the Father (John 14:9; Colossians 1:15), and in Jesus we see a man who did not sin (1 Peter 2:22; 2 Corinthians 5:21).
• Because God is holy and because He does not change, we learn that “there is no variation or shadow due to change” (James 1:17). He won’t one day become less holy. He will always be holy, so He will always be incapable of sinning.

implications for today

"Can God create a rock so heavy He cannot lift it?" Internet atheists love posing these types of "gotcha" questions to Christians. But it's like asking, "How many married bachelors are in Congress?" The question itself is nonsensical.

God not being able to sin isn't a limitation in His character. It's a recognition that, by nature, He is perfectly holy and righteous. He can't do anything contrary to His nature. Everything He does is righteous, whether we can understand it or not.

That's why any question that starts with "Why did/does God . . . ?" should be asked with a good dose of humility, not judging God as if we know better than Him. We are limited in our knowledge and our nature. Unlike Him, we are not holy (though we should all strive to be —see 1 Peter 1:15–16). It's fine to ask questions in a desire to know more about God, but we should examine ourselves to be sure we're not asking out of hubris.

If you're convicted about that, there's still good news: God's nature is also merciful. Come to Him in repentence, asking His forgiveness. He won't turn you away.