Revelation 9:18

by these three plagues, were slain, the third part of mankind, by reason of the fire and the smoke and the brimstone, that proceedeth out of their mouths;

Revelation 9:15

And the four messengers were loosed, who had been prepared for the hour, and day, and month, and year, that they should slay the third of men.

Revelation 9:17

And, thus, saw I the horses in the vision, - and them who were sitting upon them, having breastplates as of fire and hyacinth and brimstone; - and, the heads of the horses, were as heads of lions, and, out of their mouths, come forth fire and smoke and brimstone:

Treasury of Scripture Knowledge

Summary

By these three was the third part of men killed, by the fire, and by the smoke, and by the brimstone, which issued out of their mouths.

The third

Bible References

The third

Revelation 9:15
And the four messengers were loosed, who had been prepared for the hour, and day, and month, and year, that they should slay the third of men.