Malachi 2:4-7

And ye shall know that I have sent this commandment unto you, that my covenant might be with Levi, saith the LORD of hosts. My covenant was with him of life and peace; and I gave them to him for the fear wherewith he feared me, and was afraid before my name. The law of truth was in his mouth, and iniquity was not found in his lips: he walked with me in peace and equity, and did turn many away from iniquity. For the priest's lips should keep knowledge, and they should seek the law at his mouth: for he is the messenger of the LORD of hosts.