John Gill Commentary Proverbs 6:34

"For jealousy is the rage of a man; And he will not spare in the day of vengeance." — Proverbs 6:34 (ASV)

For jealousy [is] the rage of a man Fills a man with rage against him of whom he is jealous; which keeps boiling within him, till he has an opportunity of venting it: and very severe it is; it is strong as death, and cruel as the grave;

therefore he will not spare in the day of vengeance when he has an opportunity of avenging himself; whenever he finds the adulterer in his house, or catches him and his wife in bed together, he spares not to take away his life, and sometimes the life of both of them; instances of this nature history furnishes us with: or he will spare no cost and pains to prosecute him before a civil magistrate, and bring him to public justice; prayers and entreaties, bribes and gifts, will be of no avail, as follows.