Ink and Blood: The New Dead Sea Scrolls

The introduction of Angels as the bearers of the revelation is a standing feature. God does not speak in person, but gives instruction through the medium of heavenly messengers, who act as the seer's guide and is easily impersonated by normal mortal human beings to trick and deceive the gullible.

There is hardly an example of a true Apocalypse in which the instrumentality of angels in giving the message is not made prominent. In the Assumption of Moses, which consists mainly of a detailed prediction of the course of Israelite and Jewish history, the announcement is given to Joshua by Moses, just before the death of the latter. So, too, in the Sibylline Oracles, which are for the most part a foretelling of future events, the Sibyl is the only speaker.