lips. Put by Figure of speech Metonymy (of Cause), for what is spoken by them.
mouth. See above note. Illustrations: Judges 8:4-17. 2Ki 2:23, 2 Kings 2:24; Luke 19:22.
Related Commentaries of Proverbs 18:6
Proverbs 18:6
6 A fool's lips enter into contention, and his mouth calleth for strokes.