Malachi 2:4-7

So shall you know that I have sent this command to you, that my covenant with Levi may stand, says the LORD of hosts. My covenant with him was one of life and peace, and I gave them to him. It was a covenant of fear, and he feared me. He stood in awe of my name. True instruction was in his mouth, and no wrong was found on his lips. He walked with me in peace and uprightness, and he turned many from iniquity. For the lips of a priest should guard knowledge, and people should seek instruction from his mouth, for he is the messenger of the LORD of hosts.