Revelation 6:9-11

Revised Standard Version

⁹ 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 witness they had borne; ¹⁰ they cried out with a loud voice, “O Sovereign Lord, holy and true, how long before thou wilt judge and avenge our blood on those who dwell upon the earth?” ¹¹ Then they were each given a white robe and told to rest a little longer, until the number of their fellow servants and their brethren should be complete, who were to be killed as they themselves had been.