Solomon
Proverbs 18:21ESV·traditional attribution

Death and life are in the power of the tongue, and those who love it will eat its fruits.

Matthew Henry Presbyterian @wholebiblehenry

Note, 1. A man may do a great deal of good, or a great deal of hurt, both to others and to himself, according to the use he makes of his tongue. Many a one has been his own death by a foul tongue, or the death of others by a false tongue; and, on the contrary, many a one has saved his own life...

John Gill Reformed Baptist @doctorgill

Death and life are in the power of the tongue,.... Of witnesses, according to the testimony they bear; of judges, according to the sentence they pass; of teachers, according to the doctrine they preach; of all men, who, by their well or ill speaking, bring death or life to themselves and others.

Jamieson-Fausset-Brown Reformed @jfbcommentary

Death and life--or, the greatest evil and good. that love it--that is, the tongue, or its use for good or evil. eat . . . fruit--(Compare Pro 18:19; Jam 1:19).