Revelation 6:10-11

And they were crying out with a loud voice, saying: "How long, O Holy and True Lord, will you not judge and not vindicate our blood against those who dwell upon the earth?" And white robes were given to each of them. And they were told that they should rest for a brief time, until their fellow servants and their brothers, who were to be slain even as they were slain, would be completed.