# furious

very angry

# he will show no mercy

The "he" is the neighbor whose wife has committed adultery with another man. Alternate translation: "he will not limit the pain he will cause you" or "he will hurt you as much as he can" (See: [[rc://en/ta/man/translate/figs-litotes]])

# when he takes his revenge

"in the moment of his revenge" or "when the moment arrives when he can take his revenge"

# takes his revenge

If a person takes revenge, it is to cause hurt to the person who hurt him first.