Revelation 9:14-15

9:14 saying to the sixth angel, the one holding the trumpet, “Set free the four angels who are bound at the great river Euphrates!” 9:15 Then the four angels who had been prepared for this hour, day, month, and year were set free to kill a third of humanity.

Revelation 13:16

13:16 He also caused everyone (small and great, rich and poor, free and slave) to obtain a mark on their right hand or on their forehead.