Proverbs 12:17 — "An honest witness delivers truthful testimony, but a false witness tells lies" — is set within a larger framework in Proverbs where God is described as the weigher of hearts (21:2) and the one who examines the inner person. The false witness may be persuasive in the short run. But Proverbs consistently returns to the principle that the truth of a matter is known to God regardless of what the human witness says. The God who searches the heart has access to the truth the false accuser is suppressing.
Psalm 7 is written by David while he was being falsely accused by someone he had treated well: "O LORD my God, if I have done this; if there be iniquity in my hands; If I have rewarded evil unto him that was at peace with me... Let the enemy persecute my soul, and take it" (v.3–5). He submits his case to the divine court with a specific condition: if the accusation is true, let it stand. If not, let God judge. This is the posture of the falsely accused — submission of the case to the one who has all the evidence.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.