Solomon
Proverbs 13:3ESV·traditional attribution

Whoever guards his mouth preserves his life; he who opens wide his lips comes to ruin.

Matthew Henry Presbyterian @wholebiblehenry

Note, 1. A guard upon the lips is a guard to the soul. He that is cautious, that thinks twice before he speaks once, that, if he have thought evil, lays his hand upon his mouth to suppress it, that keeps a strong bridle on his tongue and a strict hand on that bridle, he keeps his soul from a great deal both of guilt...

John Gill Reformed Baptist @doctorgill

He that keepeth his mouth keepeth his life,.... He that keeps his mouth shut keeps it as with a bridle; keeps it from speaking things of other persons, particularly of such as are in high places, of kings and princes, and civil magistrates: he keeps himself quiet and comfortable; keeps himself from many troubles, which otherwise he would come into; keeps his life from danger...

Jamieson-Fausset-Brown Reformed @jfbcommentary

He . . . mouth . . . life--because evil speeches may provoke violence from others. he that openeth wide his lips shall have destruction--On last clause, compare Pro 10:14.