Revelation 6.11
From Landmark
I saw under the altar the souls of them that were slain for the word of God,
and for the testimony which they held:
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.
