18 The wicked is a ransom for the righteous; And the treacherous [cometh] in the stead of the upright.

Matthew Henry's Commentary on Proverbs 21:18

Commentary on Proverbs 21:18

(Read Proverbs 21:18)

The righteous is often delivered out of trouble, and the wicked comes in his stead, and so seems as a ransom for him.