Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power. Rev. 20:6.
What does the thousand years tell you about God, about Jesus? It tells you that God is absolutely insistent that the books are opened for everyone to see. He wants each one to understand clearly the nature of their own response to truth, and that of those around them. He is not going to do anything in secret or in hiding. He is anxious for everyone who is saved eternally to understand clearly why anyone is lost eternally.
Part of the rationale for this thousand years of investigation is the forever sealing of the universe against sin. The history of sin will be open before all, and all can see the causes and the results. We will be able to trace the working of sin, not only upon our own hearts, but upon all who ever lived on this earth. Will there be some heartaches during that thousand years? Probably so. Can God take care of that? He's big enough, isn't He? I'm not sure what will be going on, or how it's going to proceed, but I do know enough about God and about Jesus to trust Him to work it out. He knows what is best.
When the thousand years are finished, all the universe will realize that God has been fair and just every step of the way. He has never overstepped Himself. At the end of the thousand years, after the second resurrection, when the Holy City descends, and everyone who has ever lived or died meets for the first and last time, Jesus will be vindicated before all. Even Satan will admit that God has been fair and just in everything He has done.
Which side of the walls of that city would you like to be on? Do you know? Will you be watching from the inside, or will you be among those standing outside whom Satan tries to inspire for one final attack on the city? He will rush among the ones who have come forth from their graves in the second resurrection--criminals, generals of armies, sinners from every age. He tries to get them to attack the city of God. He reminds them that they are in far greater number than the ones inside. But his power is at an end. It has been proved to the entire universe that God can be trusted, and throughout the rest of eternity we will dwell in peace, for sin will never rise up the second time. None will ever again doubt God's great love.