Albert Barnes Commentary Psalms 140:11

"An evil speaker shall not be established in the earth: Evil shall hunt the violent man to overthrow him." — Psalms 140:11 (ASV)

Let not an evil speaker - literally, “A man of tongue.” That is, a man whom the tongue rules; a man of an unbridled tongue; a man who does not control his tongue. See the notes at (James 3:2–12).

Be established in the earth - Be successful or prosperous; let him not carry out his designs. It is not desirable that a man should prosper in such purposes; and therefore, this is not a prayer of malignity, but of benevolence.

Evil shall hunt the violent man ... - More literally, “A man of violence - a bad man - they shall hunt him down speedily;” or, “let him be hunted down speedily. Let him who forms a project of violence and wrong - a bad man - be hunted as the beasts of prey are, and let his destruction come quickly.” Margin, “Let him be hunted to his overthrow.” But the explanation now given suits the connection, and is a literal expression of the sense of the original.