Pretty straightforward verse: "And I saw thrones, and there were those who sat down on them, and power of judging was given them. Yes, I saw the souls of those executed with the ax for the witness they bore to Jesus and for speaking about God, and those who had worshiped neither the wild beast nor its image and who had not received the mark upon their forehead and upon their hand. And they came to life and ruled as kings with the Christ for a thousand years." The thrones and the ones that sit down on them refer to the 144,000 who get the first ressurrection (or rebirth from death) that "will rule as kings with him for the thousand years" (vs. 6; Rev 14:1-3; Rev 7:1-8; Rev 5:9, 10). They rule over those that come out of the great tribulation into to Jerusalem (Rev 7:9-15). The beast represents earthly secular governments (cross reference Daniel chapter seven), and those that have the mark of the beast are those who pay greater homage to government than to God (Mat 22:15-22). This is in line with the text elsewhere in Revelation which says: "And another angel, a third, followed them, saying in a loud voice: “If anyone worships the wild beast and its image, and receives a mark on his forehead or upon his hand, he will also drink of the wine of the anger of God that is poured out undiluted into the cup of his wrath, and he shall be tormented with fire and sulphur in the sight of the holy angels and in the sight of the Lamb." (Rev 14:9) Those that worship the beast [government] and receive the mark, will be destroyed by 'fire'. The fire here symbolizing death (Rev 20:14; 21:8).

(Revelation 20:4) "And I saw thrones, and there were those who sat down on them, and power of judging was given them. Yes, I saw the souls of those executed with the ax for the witness they bore to Jesus and for speaking about God, and those who had worshiped neither the wild beast nor its image and who had not received the mark upon their forehead and upon their hand. And they came to life and ruled as kings with the Christ for a thousand years". The length of Jehovah’s Kingdom rule by Jesus Christ and his 144,000 glorified disciples was foretold to be a thousand years. Since a thousand years is a millennium, that period is called Christ’s Millennial Reign. The expression “a thousand years” at Revelation 20:4 is not symbolic but refers to a thousand solar years. During that Millennium, Satan the Devil and his demon hordes will be in the abyss.