11 So a white robe was given to each of them, and they were told to rest a little while longer until the number would be completed of their fellow slaves and their brothers, who were going to be killed just as they had been.
“white robe” refers to those whose sins have been forgiven through faith in Jesus Christ.
God’s justice is based on His timing and His will, even though sometimes we might be impatient, it would be prudent to wait on the Lord.
12 Then I saw Him open the sixth seal. A violent earthquake occurred; the sun turned black like sackcloth made of goat hair; the entire moon became like blood;
The earthquake that will occur will be very destructive with other things hitting the earth that will most likely cause a great amount of dust to go up and block the sun from shining and cause the moon to look like blood according to Joel 2:30-31 which says, 30 I will display wonders in the heavens and on the earth: blood, fire, and columns of smoke. 31 The sun will be turned to darkness and the moon to blood before the great and awe-inspiring Day of the Lord comes.
These events show that Jesus’ return will be real close (see also Matthew 24:29).
13 the stars of heaven fell to the earth as a fig tree drops its unripe figs when shaken by a high wind;
Meteorites will bombard the earth which will contribute to darkening of the sun and kill countless of people.
14 the sky separated like a scroll being rolled up; and every mountain and island was moved from its place.
The phrase “the sky separated like a scroll being rolled up” refers that the sky will not be visible with all of the smoke from fire, dust, and debris.
Most likely a tremendous earthquake that’s off the charts will change the geography. Islands will seem to move by the earthquake by causing a bigger land mass to break into smaller islands.
15 Then the kings of the earth, the nobles, the military commanders, the rich, the powerful, and every slave and free person hid in the caves and among the rocks of the mountains.
The phrase “kings of the earth, the nobles, the military commanders, the rich, the powerful, and every slave and free person” refers to everyone, atheist, occultist, agnostic, those who denied Jesus as God, actors, all the Bill Gates (the rich) and the poorest who rejected Jesus as Lord will try to hide because they will know that they are guilty of sin. The sin of rejecting the only savior of the world, Jesus Christ and judgment is coming to them.
Atheists will no longer be an atheist and the deniers will no longer deny, that Jesus Christ is Lord of lords and King of kings.