A.T. Robertson Commentary Revelation 20:10

"And the devil that deceived them was cast into the lake of fire and brimstone, where are also the beast and the false prophet; and they shall be tormented day and night for ever and ever." — Revelation 20:10 (ASV)

Was cast (εβληθη). First aorist (prophetic, affective) passive indicative of βαλλω (verse 3).

Into the lake of fire and brimstone (εις την λιμνην του πυρος κα θειου). As in 19:20 with the two beasts, as he adds, "where are also the beast and the false prophet" (οπου κα το θηριον κα ο ψευδοπροφητης).

They shall be tormented (βασανισθησοντα). Return to the prophetic future of verses 7,8. For βασανιζω see 9:5; 14:10. For "day and night" (ημερας κα νυκτος) see 4:8; 7:15; 12:10; 14:11. For "for ever and ever" (εις τους αιωνας τον αιωνων) see 1:6,18; 4:9,10; 5:13; 7:12; 10:6; 11:15, etc. The devil was cast down from heaven (12:9), then imprisoned (20:2ff.), now he received his final doom.