And the four angels were loosed, who were prepared for an hour, and a day, and a month, and a year, to slay the third part of men.
All Commentaries on Revelation 9:15 Go To Revelation 9
Bede
AD 735
loosed: In the same manner as prophecy, which points out to us things to come, he himself in spirit sees them come to pass. And he has said four angels, because the persecution will rage in the four parts of the world. For these are they whom he saw above, standing at the four corners of the earth, and restrained from injuring the earth and the sea for the sealing of the servants of God.