Revelation 6:9-11

When he opened the fifth seal, I saw under the altar the souls of those who had been slaughtered because of the word of God and the testimony they had given.  , They cried out with a loud voice, “Lord,  the one who is holy and true,  how long until you judge those who live on the earth and avenge our blood?   ” So they were each given a white robe, and they were told to rest a little while longer until the number would be completed of their fellow servants and their brothers and sisters, who were going to be killed just as they had been.