ser'-a-fim (seraphim): A plural word occurring only in Isa 6:2 ff--Isaiah's vision of Yahweh. The origin of the term in Hebrew is uncertain. Saraph in Nu 21:6; Isa 14:29, etc., signifies a fiery serpent. A Babylonian name for the fire-god, Nergal, was Sharrapu. In Egypt there have been found eagle-lion-shaped figures guarding a grave, to which is applied the name seref. The equivalent English term is "griffin."
⇒See a list of verses on SEPHARVAIM in the Bible.
It is probable enough that popular mythology connected fire with the attendants of the deity in various ways among different peoples, and that burning lies at the base of the idea in all these suggested etymologies. It remains, however, that in Isaiah's use there is nothing of the popular legend or superstition. These seraphim are august beings whose forms are not at all fully described. They had faces, feet, hands and wings. The six wings, in three pairs, covered their faces and feet in humility and reverence, and were used for sustaining them in their positions about the throne of Yahweh. One of them is the agent for burning (with a coal off the altar, not with his own power or person) the sin from the lips of the prophet.
Seraphim are in Jewish theology connected with cherubim and ophanim as the three highest orders of attendants on Yahweh, and are superior to the angels who are messengers sent on various errands. As the cherubim in popular fancy were represented by the storm-clouds, so the seraphim were by the serpentine flashes of the lightning; but none of this appears in Isaiah's vision.
⇒See the definition of seraphim in the KJV Dictionary
In the New Testament the only possible equivalent is in "the living ones" ("beasts" of the King James Version) in Re 4:1-11; 5:1-14, etc. Here, as in Isaiah, they appear nearest Yahweh's throne, supreme in praise of His holiness.
William Owen Carver