'Messenger' in the Bible

For the priest's lips should keep knowledge, and they should seek the law at his mouth; for he is the messenger of Yahweh of Armies.

"Behold, I send my messenger, and he will prepare the way before me; and the Lord, whom you seek, will suddenly come to his temple; and the messenger of the covenant, whom you desire, behold, he comes!" says Yahweh of Armies.