A.T. Robertson Commentary Revelation 19:4

"And the four and twenty elders and the four living creatures fell down and worshipped God that sitteth on the throne, saying, Amen; Hallelujah." — Revelation 19:4 (ASV)

Fell down and worshipped God (επεσαν κα προσεκυνησαν τω θεω). Precisely as in 7:11, which see. The twenty-four elders and the four living creatures take up the antiphonal chorus of the angels.