Revelation 9:13-15

Darby Translation

¹³ And the sixth angel sounded [his] trumpet: and I heard a voice from the four horns of the golden altar which [is] before God,

¹⁴ saying to the sixth angel that had the trumpet, Loose the four angels which are bound at the great river Euphrates.

¹⁵ And the four angels were loosed, who are prepared for the hour and day and month and year, that they might slay the third part of men;