Solomon
Proverbs 30:32ESV·traditional attribution

If you have been foolish, exalting yourself, or if you have been devising evil, put your hand on your mouth.

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. An enumeration of four things which are majestic and stately in their going, which look great: - 1. A lion, the king of beasts, because strongest among beasts. Among beasts it is strength that gives the pre-eminence, but it is a pity that it should do so among men, whose wisdom is their honour, not their strength and force.

Commenting on Proverbs 30:29-33

John Gill Reformed Baptist @doctorgill

If thou hast done foolishly in lifting up thyself,.... Against a king, against whom there is no rising up; by speaking evil of him, or rebelling against him; which is acting a foolish part, since it brings a man into troubles and difficulties inextricable; or by self-commendation, which is the height of folly, and the fruit of pride; or carried it in such a haughty...

Jamieson-Fausset-Brown Reformed @jfbcommentary

As none can hope, successfully, to resist such a king, suppress even the thought of an attempt. lay . . . hand upon thy mouth--"lay" is well supplied (Jdg 18:19; Job 29:9; Job 40:4).