6:9 And when He broke the fifth seal, I saw underneath the altar the souls of those who had been slain because of the word of God, and because of the testimony which they had maintained;

And when He broke the FIFTH SEAL, I saw underneath the ALTAR the SOULS of those who had been SLAIN

These are most commonly believed to be those martyred during the tribulation period but it may include ALL martyrs since Christ's resurrection.

  1. because of the Word of God, and
  2. because of the TESTIMONY which they had maintained;

This is John's expression for true believers. He uses it for himself, Revelation 1:9 and for the overcomers, Revelation 12:10-11.

The expression "under the alter" places this part of the vision in heaven. Recall that the four horsemen under the previous four seals were sent to the earth. There is a symbolic parallel in the Old Testament sacrifices (and the blood related to that) in Leviticus 17:8-16.

It is clear from the use of "the Word of God" and "testimony" that belivers will not be killed because of their 'title' such as 'I am a Christian' or 'I am a church member at ...'. These martyrs MUST HAVE KNOWN the Word of God, and they did TESTIFY to Christ's redeeming power.

Consider:

It is for this reason, the TESTIMONY, that the devil will go to great length's to keep humans from learning, knowing, and understanding the Word of God, both inside and outside the church.

Just because the believers are removed in the uptaking, does not mean that there may not be others who will read the Word from the 1000s of Bibles left behind, video tapes left behind, and even this exposition which will be left behind. Even some of the false prophets and false teachers may realize, repent, and believe; these may be among the martyrs.