The fifth seal can be found in Revelation 6:9-11 and reads as follows…
“When He opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the testimony which they held. And they cried with a loud voice, saying, ‘How long, O Lord, holy and true, until You judge and avenge our blood on those who dwell on the earth?’ Then a white robe was given to each of them; and it was said to them that they should rest a little while longer, until both the number of their fellow servants and their brethren, who would be killed as they were, was completed.”
The fifth seal is a picture of the martyred victims who were slain during the previous seal (the fourth seal) and up until the sixteenth and seventeenth centuries, when the power of religious persecution was stopped.
“And they cried with a loud voice, saying, ‘How long, O Lord, holy and true, until You judge and avenge our blood on those who dwell on the earth?’” (Revelation 6:10).
Their cruel mistreatment cried out for vengeance just as Abel's blood cried out to God from the ground when he had been slain by his brother Cain, as we read in Genesis 4:10. Of course, the blood of Abel did not actually have a voice and speak, but in the ears of God it was heard.
So these victims, killed during the preceding times of affliction and persecution, are not in heaven, but under the altar where they had been slain. On this very important point, Dr. Adam Clarke, the great Methodist commentator, says, “The altar is upon earth, not in heaven.”
“Then a white robe was given to each of them; and it was said to them that they should rest a little while longer, until both the number of their fellow servants and their brethren, who would be killed as they were, was completed” (Revelation 6:11).
The persecutors as well as the persecuted themselves were now dead, of course. If these persecutors had passed to their punishment at death, as is by some supposed, why should the martyrs still want to call for their punishment?
In this, as in many other passages of the Bible, especially in the great prophetic books, the figure of personification is used. Things that are not, are spoken of as things that are. (See Judges 9, where we read of the trees talking with one another; also Romans 4:17.)
These martyrs had gone down as heretics under the darkness and superstition of the preceding ages. They were covered with shame before their generation, but now in the new light of liberty and reformation of Holy Scripture, their true character appears.
They are seen to be the righteous and true children of God. So white robes are given to them, for the white linen is the righteousness of saints, as we read in Revelation 19:8. Righteousness, then, is ascribed to them after they have rested a little longer where they are with all others who would follow them for their faith, and together they are raised to glorious immortality.