What does Proverbs 21:18 mean?

Throughout history God's people have suffered at the hands of wicked people, but someday God's people will be avenged. The wicked will be punished, and the righteous will be free of suffering. The meaning of this proverb seems to be that God's holy anger will turn to those who defy Him, and away from those who seek to honor His name. An earlier proverb echoed this concept in broad terms (Proverbs 11:8). When the wicked fall under God's wrath, they can no longer persecute believers, and those believers are "ransomed" from their hardships.

When Achan was punished for his treacherous act of stealing what was devoted to the Lord for destruction, he was a ransom for Israel. Israel was then able to defeat the men of Ai (Joshua 7:1—8:29). The book of Esther provides another example of the wicked becoming a ransom for the righteous. Wicked Haman passionately tried to kill righteous Mordecai. He even prepared gallows for Mordecai's execution. However, in the end Haman perished on the gallows he had built for Mordecai. God's people will not suffer forever. Someday God will wipe all tears from their eyes and punish the wicked. Until that day, we have the assurance that "the wrath of God is revealed from heaven against all ungodliness an unrighteousness of men, who by their unrighteousness suppress the truth" (Romans 1:18).