What does Proverbs 24:18 mean?

Appreciating God's justice is different from being gleeful when other people feel pain (Proverbs 17:5; 24:17). The prior verse notes that it is a sin to gloat—to celebrate or find pleasure in—the suffering of one's enemy. Here, that idea is emphasized by suggesting that God might lessen His harshness against an enemy in response to a sneering, sinful happiness over their fate. The idea is not that God will forget someone else's sins. Rather, it reiterates the idea that taking pleasure in a "wicked" person's suffering is, itself, wickedness. If both sides are wicked, why expect God to actively favor one over the other?

Instead of gloating over an enemy's trouble, believers ought to show compassion and try to lead them to repentance and faith. The wicked are like any other non-believer. Scripture compares them to lost sheep. Like the Good Shepherd, believers should endeavor to find those who are lost (Matthew 28:19–20; Luke 19:10) and bring them to God (Luke 15:4–7). Ezekiel 18:21–22 quotes the Lord as saying, "But if a wicked person turns away from all his sins that he has committed and keeps all my statutes and does what is just and right, he shall surely live; he shall not die. None of the transgressions that he has committed shall be remembered against him; for the righteousness that he has done he shall live." The following verse explains that the Lord doesn't enjoy it when people suffer, even for their own sins; He would rather they repent and be saved (Ezekiel 18:23).