A.T. Robertson Commentary Revelation 20:13

"And the sea gave up the dead that were in it; and death and Hades gave up the dead that were in them: and they were judged every man according to their works." — Revelation 20:13 (ASV)

Gave up (εδωκεν). Just "gave" (first aorist active indicative of διδωμ), but for the sea to give is to give up (effective aorist). Sea as well as land delivers its dead (all kinds of dead, good and bad). Swete notes that accidental deaths will not prevent any from appearing. Milligan is sure that the sea here means "the sea of the troubled and sinful world."

Death and Hades (ο θανατος κα ο αιδης). "An inseparable pair" (Swete) as in 1:18; 6:8; 20:14. So in Mt 16:18 "the gates of Hades" means the power of death. Etymologically Hades is the unseen world where all who die are as opposed to this visible world, but in actual use Hades is sometimes treated as the abode of the unrighteous (Luke 16:23). Charles thinks that this is true here, though there is nothing to show it apart from the personification of death and Hades and the casting of both into the lake of fire in verse 14. Here again "each man" (εκαστος) receives judgment according to his deeds (Matthew 16:27; 1 Corinthians 3:13; 2 Corinthians 5:10; Romans 2:6; Romans 14:12; 1 Peter 1:17; Revelation 2:23).