The 144,000 are sealed with a mark on the forehead, just like Cain was in Genesis, to keep them from being harmed. The other believers will not be sealed, and they will be able to be harmed, killed, martyred, destroyed by plagues, etc.
The word seal does not have to always refer specifically to the Holy Spirit, though it is true that the 144,000 will have the Holy Spirit, and so it probably does refer to it.
Hmm interesting about getting the Holy Spirit from the 2 Witnesses only. I just don't think God works that way-- in the Old Testament people did not have to receive the Holy Spirit to be saved, they had to believe God. I believe that is the fact across all ages--to be saved from your sins, you have to believe in the Savior to save you from your sins. The Holy Spirit dwelling within is not what determines if someone is saved (for they did not have His indwelling continually in the Old Testament, but we do have Him indwelling us continually in the Church age). The indwelling of the Spirit is a special blessing to us in the Church Age that never happened in a previous age, and evidently, may not happen in any other age to come (for mortals). However, it does seem that the 144,000 are an exception to this case--they will have the indwelling of the Spirit during their part of the 7 years, but not the millions of other people who turn to Christ during that period.
One thing is for sure--the 2 Witnesses will explain it thoroughly when they arrive on the scene. It may be somewhat of a mystery for us now, as it doesn't apply to us anyway.
None of the 144,000 will lose their souls.
MANY more than the 144,000 will be saved during the 70th Week.
The 144,000 will be sealed for their protection. This is what the passage says. However, this may also refer to the Spirit indwelling them. But it is specifically for their protection.
Rev. 14 does seem to indicate a rapture for the 144,000--that is to say, they get their own special treatment. See Rev. 14.
I just noticed the numerical significance of Revelation chapter 14, and verse 4. 14:4 is like 144. Like 144,000.
Rev 14:4 These are they which were not defiled with women; for they are virgins. These are they which follow the Lamb whithersoever he goeth. These were redeemed from among men, being the firstfruits unto God and to the Lamb.
