What is the term for someone who speaks on behalf of a deity? Not that the deity speaks through them or channels through them1, but that they speak on behalf of the deity. Like when an angel speaks on behalf of God. Here, an angel conveys God's message for Him. God Himself does not convey the message.
I've thought of mouthpiece:
a person or organization who speaks on behalf of another person or organization.
the media acts as a mouthpiece for the Party
But I would like to know if there are other more suitable words.
1 Clarification: When God speaks through a being (for example, a donkey), He is projecting His voice through the being to convey His message; that is, God Himself is delivering the message, not appointing someone to deliver the message for Him. This is not what I'm looking for.