Jerome

The law of truth was in his mouth, and iniquity was not found on his lips. He walked with me in peace and equity, and turned many away from iniquity. LXX: The law of truth (also called truth itself) was on his lips, and iniquity was not found on his tongue. He walked with me in peace and turned many away from wickedness. The law of truth was on his lips, that is, the teaching of the peoples, which in the priest should not be defiled by any falsehood; but should proceed entirely from the fountain of truth. …

Commentary on Malachi ↗