Revelation 9:18-21

One third of mankind was killed by these three plagues --- the fire, the smoke and the sulphur, which proceeded out of the horses' mouths.

Revelation 16:1-21

Then I heard a loud voice from the Temple saying to the seven angels, "You [angels], go and pour out the seven bowls of God's wrath 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
One third of mankind was killed by these three plagues --- the fire, the smoke and the sulphur, which proceeded out of the horses' mouths.
Revelation 16:9
And people were seared by the intense heat, and they cursed the name of God, who had control over these judgments [i.e., the authority to inflict them], but they refused to repent and honor God. [See verse 2].

General references

Matthew 24:39
And the people [i.e., of Noah's day] did not know [when it would happen] until the Flood came and swept them all away. It will be the same way when the presence of the Son of man [arrives].