Proverbs 29:9

If a wise man contendeth with a foolish man, whether he rage or laugh, there is no rest.
– Proverbs 29:9

The contention here is an unreconciled complaint. The result is coming to no resolution because the contention is with a foolish man. The words of the wise are presented as calm and reasonable (Proverbs 15:23; 17:27), but a determined fool cannot be reasoned with (Proverbs 12:15). The fool’s response may range from anger to mockery, but there will be no rest, or peace. The wise discern the time to leave off speaking to a fool.