Re 20:4 And I saw thrones, and they sat upon them, and judgment was given unto them: and I saw the souls of them that were beheaded for the witness of Jesus, and for the word of God, and which had not worshipped the beast, neither his image, neither had received his mark upon their foreheads, or in their hands;
These martyred are NOT part of the first resurrection as they are resurrected prior to the first resurrection after Christ returns. I would say after 3 days in the grave all martyred are resurrected. Biblical examples....
2. Two Witnesses
3. 24 elders - Note 12 of these elders were resurrected at the cross the other 12 are the apostles which died a martyr's death. Crowns and white raiment signifies resurrection.
3. Martyred in Verse 20:4
Martyred verse 20:4
Of course it does not say that they are resurrected in three days however when we look at this group we see
1. Only martyred are mentioned here in verse 4 no others. This important fact seems to be glossed over when trying to understand the first resurrection and the rest of the dead in chapter 20. When we see this then we need to ask where are the rest of the dead believers? The rest of the dead....
2. They are ALIVE. This group is reigning and LIVING with Christ whereas the other group is yet to be made alive but still reigns and are priests of God. At the first resurrection they too will be made alive.
Re 20:4 and they lived and reigned with Christ a thousand years.
Rest of the dead (believers)
Re 20:6 but they shall be priests of God and of Christ, and shall reign with him a thousand years.
3. Judgment has been given them.
Mt 16:27 For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works.
There is a reward for a martyr's death and rightfully so. The reward is an earlier resurrection to life and not wait in the grave until Christ returns.