A false witness shall not be unpunished,.... He that bears false witness against his neighbour in an open court of judicature; though be may not be detected by men, and so escape the punishment due to such offenders by the laws of God and men; yet God, who knows all hearts and actions, will not suffer him to go with impunity; if not punished in this world, he shall be in the world to come; for bearing false witness, or perjury, is a grievous offence to God;
and he that speaketh lies shall not escape; even he that useth himself to lying in private conversation shall not escape the reproach of men; for nothing is more scandalous than lying; nor the wrath of God, such shall have their portion in the lake which burneth with fire and brimstone, Revelation 21:8.

Those that tell lies in discourse, are in a fair way to be guilty of bearing false-witness.

Compare Proverbs 19:9, where perish explains not escape here (compare Psalm 88:9-10).

In Proverbs 19:5 and Proverbs 19:9 we have the introductory proverb of two groups, the former of which, in its close as well as its beginning, cannot be mistaken.
5 A lying witness remaineth not unpunished;
And he who breathes out lies escapeth not.
Regarding יפיח, vid., vol. i, p. 148: as here we read it of false witness at Proverbs 6:19; Proverbs 14:5, Proverbs 14:25. לא ינּקה occurs four times before, the last of which is at Proverbs 17:5. The lxx elsewhere translates יפיח כזבים by ἐκκαίειν ψευδῆ, to kindle lies; but here by ὁ δὲ ἐκαλῶν ἀδίκως, and at Proverbs 19:9 by ὃς δ ̓ ἂν ἐκκαύσῃ κακίαν, both times changing only because ψευδής goes before, and instead of ψευδῆ, the choice of a different rendering commended itself.