"And I looked when He broke the sixth seal, and there was a great earthquake; and the sun became black as sackcloth made of hair, and the whole moon became as like blood; and the stars of the sky fell to the earth, as a fig tree casts its unripe figs when shaken by a great wind. And the sky was split apart like a scroll when it is rolled up; and every mountain and island were moved out of their places. And the kings of the earth and the great men and the commanders and the rich and the strong and every slave and free man, hid themselves in the caves and among the rocks of the mountains; and they said to the mountains and to the rocks, 'Fall on us and hide us from the presence of Him who sits on the throne, and from the wrath of the Lamb; for the great day of their wrath has come; and who is able to stand?'" (Rev. 6:12-17 NASB).
[Art used by permission by Pat Marvenko Smith, copyright 1992. Click here to visit her "Revelation Illustrated" site.]
Remember the oil field fires (photo right) in Kuwait that Sadam Hussain had set as his armies were driven out at the end of the Gulf War? What an apocalyptic site: the sun, with it's ominous darkness, and the moon, with it's eerie dark, blood-red color, and the black smoke added to this ruinous, "end-of-the-world" scene. No, this wasn't the sixth seal of Revelation, but it is a good local illustration of what it will look like worldwide as a result of wars, earthquakes and perhaps volcanic activity or possibly a lunar eclipse. Lunar eclipses may be seen from the whole nightside of the planet and last for hours. During such an event the Moon turns the colour of blood. It is the report by Josephus of a lunar eclipse which allows us to date the chronology of Jesus Christ (Antiq. 17.6.4). This is not symbolic; it is a real sign precluding the day of the Lord, God's wrath. Peter preached this Old Testament prophecy at Pentecost (Acts 2:14-21; c.f., Joel 2:28-32), knowing this was the next event associated with the pouring out of the Holy Spirit as Israel enters the millennial kingdom; but Israel didn't believe her Messiah, so the dispensation of grace (the church age) began with Paul instead and Israel was postponed for nearly 2,000 years (Rom. 11:1-36).
"The stars of the sky fall(ing) to the earth" are probably Satan and his angels being cast down from heaven to the earth (Rev. 12:7-17). The splitting and rolling up of the sky reveals God's throne (in the third heaven) to all the inhabitants of the earth just prior to the beginning of His judgment. No wonder all the inhabitants of the earth try to hide from God's wrath; "for the great day of their wrath has come; and who is able to stand?" Concluding the sixth seal is this statement, just before the seventh seal is broken open.
The Greek tense for "wrath has come" in verse 17 of Revelation chapter six is the aorist tense. The same example is found in Mark 14:41, where in the garden of Gethsemane Jesus says, "the hour has come." The very next event is His arrest. God's wrath too is about to come with the breaking of the seventh seal.
Only two events are between the sixth and seventh seals; the sealing of the 144,000 Jews from the twelve tribes and "a great multitude, which no one could count" in heaven (See: Rev. chapter 7). The 144,000 Jews are sealed to protect them from God's wrath to come on the whole earth, and the "great multitude" is the church (the body of Christ) raptured to heaven just prior to His wrath. That wrath begins in Revelation 8:1, with the opening of the scroll by breaking it's seventh and last seal--introducing the "seven trumpets" of wrath.
Included below is a study chart of "pivotal" verses demonstrating how the sign of the sun and moon is associated and just prior to the day of the Lord: