The one who speaks what is faithful declares an honest testimony,
but a false witness utters deceit. Bible see other translations

“speaks what is faithful.” The Hebrew is more compact: “speaks faithfulness,” but that is not as clear in English. The person who speaks faithful things, which in this context means what is faithful to God and to what he has been taught, will speak “righteousness,” the things that are right and make people righteous in the sight of God. The person who turns away from God and what he has been taught will speak unrighteousness; that which is unrighteous in the sight of God.

Commentary for: Proverbs 12:17