Solomon
Proverbs 26:4ESV·traditional attribution

Answer not a fool according to his folly, lest you be like him yourself.

Matthew Henry Presbyterian @wholebiblehenry

See here the noble security of the scripture-style, which seems to contradict itself, but really does not. Wise men have need to be directed how to deal with fools; and they have never more need of wisdom than in dealing with such, to know when to keep silence and when to speak, for there may be a time for both. 1.

Commenting on Proverbs 26:4-5

John Gill Reformed Baptist @doctorgill

Answer not a fool according to his folly,.... Sometimes a fool, or wicked man, is not to be answered at all; as the ministers of Hezekiah answered not a word to Rabshakeh; nor Jeremiah the prophet to Hananiah; nor Christ to the Scribes and Pharisees; and when an answer is returned, it should not be in his foolish way and manner, rendering evil for evil...

Jamieson-Fausset-Brown Reformed @jfbcommentary

Answer not--that is, approvingly by like folly.