Revelation 15:3 - Ellicott's Commentary On The Whole Bible

And they sing the song of Moses the servant of God, and the song of the Lamb. — They join their voices to the music of their harps. The song of Moses was a pæan of victory over Pharaoh and his hosts (Exodus 14:26-31; Exodus 15:1-21). Israel stood on the margin of the Red Sea and saw the tokens of the overthrow of the great world-power of that day; so these saints stand by the border of the fire-blent sea of glass, and sing the song of triumph over the doom of the great world-powers of every age. The cases are parallel, the songs are alike; and it would not be out of place were the words of that other song of Moses, the man of God, to be heard from those who are made glad according to the days of their affliction, and who are clothed with the beauty of the Lord their God (Psalms 90:1; Psalms 90:15; Psalms 90:17). They also sing the song of the Lamb. The Apocalypse is full of Christ; the Lamb is the axis on which the world of its scenery moves; He is the key of earth’s history; the victory of the saints is in Him (Revelation 12:11); their song of triumph is of Him who put a new song in their mouth and in whom all things are reconciled (Ephesians 1:10; Philippians 2:10-11).