The seven angels with the seven last plagues.
Revelation 15:1 And I saw another sign in the heaven, great and wonderful, seven messengers having the seven last plagues, because in these was completed the wrath of God, Revelation 15:2 and I saw as a sea of glass mingled with fire, and those who do gain the victory over the beast, and his image, and his mark, [and] the number of his name, standing by the sea of the glass, having harps of God,
The song of them that overcome the beast.
Revelation 15:3 and they sing the song of Moses, servant of God, and the song of the Lamb, saying, 'Great and wonderful [are] Thy works, O Lord God, the Almighty, righteous and true [are] Thy ways, O King of saints, Revelation 15:4 who may not fear Thee, O Lord, and glorify Thy name? because Thou alone [art] kind, because all the nations shall come and bow before Thee, because Thy righteous acts were manifested.' Revelation 15:5 And after these things I saw, and lo, opened was the sanctuary of the tabernacle of the testimony in the heaven; Revelation 15:6 and come forth did the seven messengers having the seven plagues, out of the sanctuary, clothed in linen, pure and shining, and girded round the breasts with golden girdles:
The seven vials full of the wrath of God.
Revelation 15:7 and one of the four living creatures did give to the seven messengers seven golden vials, full of the wrath of God, who is living to the ages of the ages; Revelation 15:8 and filled was the sanctuary with smoke from the glory of God, and from His power, and no one was able to enter into the sanctuary till the seven plagues of the seven messengers may be finished.