John Gill's Exposition of the Whole Bible
Proverbs 21:28
A false witness shall perish,.... As witness he shall perish in his reputation, no credit shall be given him, he shall not be admitted an evidence, or a witness in any cause, being found a false one; and as a man, he shall be punished in body or estate by the civil magistrate, and his soul shall perish eternally, unless he has true repentance for his sin: or, a witness of lies shall perish k it may be applied to any teacher of false doctrine; and to the man of sin, and his followers, that speak lies in hypocrisy; everyone that loves and makes a lie shall die the second death, and be excluded from eternal happiness, Revelation 21:8;
but the man that heareth; before he speaks, and speaks what he hears, and does not devise things himself; but witnesses the truth, and nothing else, to the best of his knowledge:
speaketh constantly; invariably and consistently, what is all of a piece, and by which he ah, des; or "continually", as Jarchi; or "for ever"; he is made use of as a witness as long as he lives, whenever there is occasion for him; the Vulgate Latin version renders it, "he speaks victory"; his testimony, being true and valid, carries the cause: it, nay be applied to a faithful teacher, who hearkens to the word of God, and speaks according to that; such an one speaks out, he doctrine of the word constantly, boldly, with certainty, without any hesitation or staggering.
k עד כזבים "testis mendaciorum", Montanus, Junius Tremellius, Cocceius, Gejerus, Michaelis, Schultens.