Proverbs 12:17 - Matthew Poole's English Annotations on the Holy Bible

He that speaketh truth, Heb. He that will speak truth, i.e. he who accustometh himself to speak truth in common conversation; for the future tense in the Hebrew tongue oft notes a continued act or habit. Showeth forth righteousness, to wit, as a witness in public judgment; he will speak nothing but what is true and just; you may depend upon his testimony. But a false witness deceit; he who useth himself to lying in his common talk will use falsehood and deceit in judgment.