Revelation 9:14-15, 20

saying to the sixth angel who had the trumpet, “Release the four angels who are bound at the great river Euphrates.” So the four angels, who had been prepared for the [appointed] hour and day and month and year, were released to kill a third of mankind.

The rest of mankind, who were not killed by these plagues, did not repent even then of the works of their hands, so as to cease worshiping and paying homage to the demons and the idols of gold and of silver and of bronze and of stone and of wood, which can neither see nor hear nor walk; [Ps 115:4-7; 135:15-17; Is 17:8]