Isaiah 6:2-3. ("God's attendant angels".) Seraphim (plural) in Numbers 21:6 means the "fiery flying (not winged, but rapidly moving) "serpents" which bit the Israelites; called so from the poisonous inflammation caused by their bites. Burning (from saraph "to burn") zeal, dazzling brightness of appearance (2 Kings 2:11; 2 Kings 6:17; Ezekiel 1:13; Matthew 28:3) and serpent-like rapidity in God's service, always characterize the seraphim. Satan's "serpent" (nachash) form in appearing to man may have some connection with his original form as a seraph (singular) of light. The serpent's head symbolized wisdom in Egypt (2 Kings 18:4). Satan has wisdom, but wisdom not sanctified by the flame of devotion. The seraphim with six wings and one face differ from the cherubim with four wings (in the temple only two) and four faces (Ezekiel 1:5-12); but in Revelation 4:8 the four living creatures (zooa) have each six wings. The "face" and "feet" imply a human form.
Seraphim however may come from sar, "prince" (Daniel 10:13); "with twain he covered his face, and with twain he covered his feet, and with twain He did fly." Two wings alone of the six were kept ready for instant flight in God's service; two veiled their faces as unworthy to look on the holy God or pry into His secret counsels which they fulfilled (Exodus 3:6; Job 4:18; Job 15:15; 1 Kings 19:13). Those in the presence of Eastern monarchs cover the whole of the lower part of their persons (which the "feet" include). Service consists in reverent waiting on, more than in active service for, God. Their antiphonal anthem on the triune God's holiness suggests the keynote of Isaiah's prophecies, "Holy, holy, holy is Jehovah of hosts; the fullness of the whole earth (is) His glory" (Psalm 24:1; Psalm 72:19).
Besides praising God they are secondly the medium of imparting spiritual fire from God to His prophet; when Isaiah laments alike his own and the people's uncleanness of lips, in contrast to the seraphim chanting in alternate responses with pure lips God's praises, and (Isaiah 6:5-7) with a deep sense of the unfitness of his own lips to speak God's message to the people, one of the seraphim flew with a live coal which he took from off the altar of burnt offering in the temple court, the fire on it being that which God at first had kindled (Leviticus 9:24), and laid it upon Isaiah's mouth, saying, "lo, this hath touched thy lips, and thine iniquity is taken away and thy sin purged." Thus he was inaugurated in office, as the disciples were by the tongues of fire resting on them, the sign of their speaking of Jesus in various languages; his unfitness for the office, as well as his personal sin, were removed only by being brought into contact with the sacrificial altar, of which Messiah is the antitype.