en_tn/pro/21/18.md

is ransom for

The word "ransom" is a metaphor for one person who takes the place of another person. Here the person who does what is wrong is punished instead of the person who does what is right. (See: rc://en/ta/man/translate/figs-metaphor)

the treacherous

a person who harms those who trust him by lying and otherwise dealing falsely

upright people

"righteous people" or "honest people" or "just people"