Proverbs 21:18

18 The godless becometh a ransom for the righteous; And the faithless cometh into the place of the upright. The thought is the same as at Pro 11:8. An example of this is, that the same world-commotion which brought the nations round Babylon for its destruction, put an end to Israel's exile: Cyrus, the instrument in God's hands for inflicting punishment on many heathen nations, was Israel's liberator, Isa 43:3. Another example is in the exchange of places by Haman and Mordecai, to which Rashi refers. כּפר is equivalent to λύτρον, ransom; but it properly signifies price of atonement, and generally, means of reconciliation, which covers or atones for the guilt of any one; the poll-tax and "oblations" also, Exo 30:15., Num 31:50, are placed under this point of view, as blotting out guilt: if the righteousness of God obtains satisfaction, it makes its demand against the godless, and lets the righteous go free; or, as the substantival clause 18b expresses, the faithless steps into the place of the upright, for the wrath passes by the latter and falls upon the former. Regarding בּוגד, vid., Pro 2:22. Thus, in contrast to the ישׁר, he is designated, who keeps faith neither with God nor man, and with evil intention enters on deceitful ways - the faithless, the malicious, the assassin.

This intimates, 1. What should be done by the justice of men: The wicked, that are the troublers of a land, ought to be punished, for the preventing and turning away of those national judgments which otherwise will be inflicted and in which even the righteous are many times involved. Thus when Achan was stoned he was a ransom for the camp of righteous Israel; and the seven sons of Saul, when they were hanged, were a ransom for the kingdom of righteous David. 2. What is often done by the providence of God: The righteous is delivered out of trouble, and the wicked comes in his stead, and so seems as if he were a ransom for him, Pro 11:8. God will rather leave many wicked people to be cut off than abandon his own people. I will give men for thee, Isa 43:3, Isa 43:4.

21:18 The wicked will fall prey to the traps they set for others (26:27; see also 11:8).