What does Revelation 9:12 mean?

The final verse of chapter 8 warned that there were three trumpet judgments yet to come, worse even than the first four (Revelation 8:13). Chapter 9, so far, has focused entirely on the fifth trumpet judgment, which is the "first woe" of those three. Two more—the sixth and seventh trumpet judgments—lie ahead.

The word "woe" indicates severe suffering and distress. The tribulation is a seven-year period of severe end-times suffering and distress. The second half of this era, called the great tribulation, increases the severity of God's judgment on unbelievers as He pours out His wrath upon them. In His Olivet Discourse Jesus advised righteous Jews to flee to the mountains when an idolatrous image stands in the holy place. He remarked, "Pray that your flight may not be in winter or on a Sabbath. For then there will be great tribulation, such as has not been from the beginning of the world until now, no, and never will be" (Matthew 24:20–21). Believers today should be extremely grateful that God has saved us from the wrath to come (1 Thessalonians 1:10).