The Zohar, Chapter “Pekudei (Accounts),” Item 528: When a person passes away from this world, this animal comes out on four flying seraphim. They fly in front of him and it does not let all those evokers of judgment and sentence approach him. There are several messengers of peace around him, which are the seraphim. When they travel and are seen, those serpents and seraphim that come out of the serpent, who caused death to the entire world, surrender.
The snake, the beasts, and the angels, all of these are inner forces of the level lower than that of man. We are speaking here of the form in which these forces and inclinations come forth from each one of us, how with their help we connect between us, between all the souls, and gradually create a network between us, which becomes more and more corrected and thus comes closer and closer to the real Malchut of Infinity that always serves us as a criterion. Thus in all of these actions, we need to see the forces of connection between us.
From the 2nd part of the Daily Kabbalah Lesson 11/1/2011, The Zohar