Revelation 6:9-11 - The Fifth Seal
9 And when he opened the fifth seal, I saw under the altar the souls of those killed for the word of God and for the testimony which they had. 10 And they cried with a loud voice, saying, How long, Master, holy and true, do you not judge and avenge our blood on those that dwell on the earth? 11 And a white robe was given them, and it was told them to rest yet a little while, till their fellow servants and their brothers and those about to be killed as they also had been should finish [their testimony].