Isaiah 6:2

stood--not necessarily the posture of standing; rather, were in attendance on Him [MAURER], hovering on expanded wings. the--not in the Hebrew. seraphim--nowhere else applied to God's attendant angels; but to the fiery flying (not winged, but rapidly moving) serpents, which bit the Israelites (Num 21:6), called so from the poisonous inflammation caused by their bites. Seraph is to burn; implying the burning zeal, dazzling brightness (Kg2 2:11; Kg2 6:17; Eze 1:13; Mat 28:3) and serpent-like rapidity of the seraphim in God's service. Perhaps Satan's form as a serpent (nachash) in his appearance to man has some connection with his original form as a seraph of light. The head of the serpent was the symbol of wisdom in Egypt (compare Num 21:8; Kg2 18:4). The seraphim, with six wings and one face, can hardly be identified with the cherubim, which had four wings (in the temple only two) and four faces (Eze 1:5-12). (But compare Rev 4:8). The "face" and "feet" imply a human form; something of a serpentine form (perhaps a basilisk's head, as in the temples of Thebes) may have been mixed with it: so the cherub was compounded of various animal forms. However, seraph may come from a root meaning "princely," applied in Dan 10:13 to Michael [MAURER]; just as cherub comes from a root (changing m into b), meaning "noble.

— Jamieson-Fausset-Brown Commentary (public domain)