C. F. Keil and Franz Delitzsch on Proverbs 25:18

Pro 25:18 18 A hammer, and a sword, and a sharp arrow -      A man that beareth false witness against his neighbour.

An emblematic, or, as we might also say, an iconological proverb; for 18a is a quodlibet of instruments of murder, and 18b is the subscription under it: that which these weapons of murder accomplish, is done to his neighbour by a man who bears false witness against him - he ruins his estate, takes away his honour, but yet more: he murders him, at one time more grossly, at another time with more refinement; at one time slowly, at another time more quickly. מפיץ, from פּוּץ, is equivalent to מפּץ, and מפּץ from נפץ; the Syr. and Targ. have instead פדועא (פדיעא) from פּדע = פּצע; the word פּריעא, on which Hitzig builds a conjecture, is an error of transcription (vid., Lagarde and Levy). The expression, 18b, is from the decalogue, Exo 20:16; Deu 5:17. It is for the most part translated the same here as there: he who speaks against his neighbour as a false witness. But rightly the lxx, Jerome, the Venet., and Luther: false testimony. As אל sA .y signifies both that which is mighty = power, and Him who is mighty = God, so עד signifies both him who bears testimony and the testimony that is borne, properly that which repeats itself and thereby strengthens itself; accordingly we say ענה עד, to give testimony in reply - viz. to the judge who asks - or generally to offer testimony (even unasked); as well as ענה לעד, Deu 31:21, i.e., as evidence (Jerome, pro testimonio). The prep. ב with this ענה has always the meaning of contra, also at 1Sa 12:3; Gen 30:33 is, however, open to question.