Revelation 6:9-11, "
9 And when he had opened the fifth seal, I saw
under the altar the souls of them that were slain for
the word of God, and for the testimony which they
held:
10 And they cried with a loud voice, saying, How
long, O Lord, holy and true, dost thou not judge and
avenge our blood on them that dwell on the earth?
11 And white robes were given unto every one of
them; and it was said unto them, that they should
rest yet for a little season, until their fellowservants
also and their brethren, that should be killed as they
were, should be fulfilled."