Revelation 20:4 And I saw thrones, and they 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 worshiped 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.
The promise here is about the eternal destiny of believers in Christ: they will sit on thrones and be given authority to judge. We shall rule as kings over all sin and evil forever with God-given authority and power. We, as eternal subjects of the Lord, will never sin again and surrender authority to any evil power. We will be absolutely perfect in willing obedience to God, our Father and Creator. In this way we will rule and judge, under Christ, over Sin, Death, and Satan forever, world without end.
The surprising, and little known, aspect of this promise is that we live and reign with Christ now, during this time, even as we speak, for a thousand years. The “thousands years,” the millennium, is the period in which we are living right now, between the Ascension and the Second Coming of Christ. “[God] raised us up with him and seated us with Him in the heavenly places in Christ Jesus [Ephesians 2:6].” This is the position from which baptized believers now reside and reign.
Of course, we are still contending with the usurper, the prince of the power of the air, for the right to rule the hearts and souls of created and redeemed people. But “the gospel is the power of God.” The just live by faith. We live today and reign with Christ by faith in the Gospel. We live and rule with that promise.