What does Proverbs 24:29 mean?

A common modern English phrase is, "I don't get mad. I just get even." The first part of that adage seems biblical (Psalm 37:8–9; Proverbs 16:32; Colossians 3:8), but the second is entirely wrong. One attempts to "settle the score" by hurting another. That person strikes back, as they see it, to also "make things even." The first party disagrees and thinks this requires more, and more extreme measures. Neither ever agrees justice has been reached, so the cycle never concludes easily. Petty offenses turn into feuds and insults lead to open war. Romans 12:17 commands: "Repay no one evil for evil." Hebrews 10:30 reminds us again that vengeance belongs to the Lord. When a believer believes someone has wronged him, he should resist the temptation to hurt that person (Proverbs 20:22). Instead, he should trust the Lord to do the right thing.

Another reason to avoid taking revenge is that God is much better at it than we are. Paul's admonition about vengeance in Romans suggests one ought to "leave it to the wrath of God, for it is written, 'Vengeance is mine, I will repay, says the Lord'" (Romans 12:19). Paul cites Deuteronomy 32:35 where God takes on the role of an avenger. Psalm 94:1 also refers to the Lord as "God of vengeance." Whatever we think we might accomplish by our feeble efforts, the best response to sin and insults is to let the God of the universe make things right.