John Gill Commentary Proverbs 25:18

"A man that beareth false witness against his neighbor Is a maul, and a sword, and a sharp arrow." — Proverbs 25:18 (ASV)

A man that bears false witness against his neighbour In whose house he has often been, and whom he has frequently visited; and, observing what was done there, not only discovers and tells abroad the secrets of his family, but even things which are false; yea, in a court of judicature, appears a witness against him, and swears falsely to his hurt and prejudice.

Such a man [is] a maul, and a sword, and a sharp arrow ; that is, to his neighbour, against whom he bears false witness; and, by so doing, he mauls his fame, his credit, character, and reputation; and, as with a sword, takes away his life; and against whom there is no more guarding than against a sharp arrow, that comes from afar, suddenly and swiftly.