Verse 1
1) "And I saw an angel come down from heaven," (kai eidon angelon katabainonta ek tou ouranou) "And I saw (recognized) an angel coming down out of heaven;" from where he had fought with the Devil and his Angels in defense of God’s people and property, Revelation 12:7-8. Whether this was Jesus Christ or Michael, one of his chief Angelic servants to whom he had committed the key to bind Satan is not clear, Revelation 1:18.
2) "Having the key of the bottomless pit," (echonta ten klein tes abussou) "Holding the key of the abyss, the bottomless pit,” as Christ holds the keys of hell and death, each of which he has conquered for believers (Hebrews 2:14; Revelation 1:18), So does this Angel, perhaps Michael, the Angelic defender of God’s people and property, here hold the key of the bottomless pit, in preparation for opening and casting Satan therein, See also Revelation 9:1; Revelation 9:11; Revelation 12:7-8.
3) "And a great chain in his hand," (kai halusin megalen epi ten cheira autou) "And (having) a great chain upon (in) his hand;" carrying a chain, holding a key to this bottomless pit, the angel came down with great power and a fixed purpose; as angels (demon spirits) under Satan’s control are now said to be under chains (restraints) until the final judgment, even so it is to be considered that Satan is to be placed under more severe restraints and restricted to activities in the bottomless pit alone during the Millennial age, Judges 1:6.