Revelation 6:10-11

and they cried out with a loud voice, saying, “How long, O Master, holy and true? Will You not judge and avenge our blood on those who dwell on the earth?” And a white robe was given to each of them; and it was told to them that they should rest for a little while longer, until the number of their fellow slaves and their brothers who were to be killed even as they had been, would be completed also.