King James Version (KJV) - Revelation 9:15 >

And the four angels were loosed, which were prepared for an hour, and a day, and a month, and a year, for to slay the third part of men.

Berean Study Bible (BSB) - Revelation 9:15 >

So the four angels who had been prepared for this hour and day and month and year were released to kill a third of mankind.