Revelation 6:9-11 - The Fifth Seal
9 And when He opened the fifth seal, I saw under the altar the souls of those that had been slain for the word of God, and for the testimony which they maintained. 10 And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on those that dwell upon the earth? 11 And white robes were given to each of them, and it was told them to rest a little while longer, till the number of their fellow-servants, and their brethren that should be killed as they were, should be complete.