Revelation 20:4,5

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; and they lived and reigned with Christ a thousand years.

5  But the rest of the dead lived not again until the thousand years were finished. This is the first resurrection.

This passage is talking about the resurrection of the tribulation saints. It says that all who take part in this first resurrection will live and rule with Christ through the thousand-year period. The passage indicates that those who die and who are not raised in the first resurrection will not live again until after the thousand years are finished. This chapter says  six times  that the time period of the Lord's Kingdom on earth is a thousand years.  The amillennial theology that says this period is an unknown period of time is beyond common reason. The rule of the saints for this thousand-year period starts at the end of the great tribulation.