"Revelation 6: 9-11" ()
These martyrs are people who came to faith since the resurrection of the saints possibly by the preaching of the 144,000 Jewish Evangelists (page 22). When the saints disappeared possibly this caused many people who had heard of ‘the resurrection’ to finally make a decision for the Lord.
The Holy Bible (KJVA)
Revelation (REV) 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.