Revelation 9:18-21

Through these three Curses a third of mankind perished--because of the fire, and the smoke, and the sulphur that issued from their mouths;

Revelation 16:1-21

Then I heard a loud voice, which came from the Temple, saying to the seven angels-- 'Go and empty the seven bowls of the Wrath of God upon the earth.'

Treasury of Scripture Knowledge

Summary

Therefore he hath poured upon him the fury of his anger, and the strength of battle: and it hath set him on fire round about, yet he knew not; and it burned him, yet he laid it not to heart.

General references

Bible References

He knew

Revelation 9:18
Through these three Curses a third of mankind perished--because of the fire, and the smoke, and the sulphur that issued from their mouths;
Revelation 16:9
and men were scorched by the intense heat. They blasphemed the Name of God who controlled these Curses, yet they did not repent and give him praise.

General references

Matthew 24:39
Taking not notice till the flood came and swept them one and all away; and so will it be at the Coming of the Son of Man.