'Mercy and Truth' in the Bible

Let not mercy and truth forsake thee: bind them about thy neck; write them upon the table of thine heart:

Do they not err that devise evil? but mercy and truth shall be to them that devise good.

By mercy and truth iniquity is purged: and by the fear of the LORD men depart from evil.

Mercy and truth preserve the king: and his throne is upholden by mercy.