During the thousand-year period preceding the final judgment of God, the people of God do not sit still.
“Blessed and holy is he who has part in the first resurrection. Over such the second death has no power, but they shall be priests of God and of Christ, and shall reign with Him a thousand years” (Revelation 20:6).
Each member of the community of Jesus, who went along with Him after the great day, will reign together with Him. What does this mean? God's people consist of many millions or perhaps even billions of people. So, will there be a huge palace with hundreds of millions of thrones for everyone to sit on and hold sway? And who will be ruled over? In other words, what does it mean that God's people will rule as kings?
The core quality of the king in Israel was the ability to make righteous judgments. King Solomon is the classic example. He asked God for wise judgment. According to God, he hit the nail right on the head. The core business of leading and governing is forming (and carrying out) righteous judgments. That is what good kings do! To rule as kings means that God gives His people the opportunity to make a good, fair and just judgment about world history.
Paul refers to this engagement in Gods judgement in passing in his first letter to the Corinthians. While discussing the conflicts at play in Corinth, he says:
“(…) Do you not know that the saints will judge the world. And if the world will be judged by you, are you unworthy to judge the smallest matters? Do you not know that we shall judge angels? How much more things that pertain to this life?” (I Corinthians 6:1-3).
Jesus indicates that the Queen of Sheba and the people of Nineveh will play a part in assessing the corrupt religious leadership of his own day:
“The men of Nineveh will rise up in the judgement with this generation and condemn it, because they repented at the preaching of Jonah; and indeed a greater than Jonah is here. The queen of the South will rise up in the judgment with this generation and condemn it, for she came from the ends of the earth to hear the wisdom of Solomon; and indeed a greater than Solomon is here” (Matthew 12:41-42).
So, God's people will gain insight into His judgments and will even be actively involved in it. This of course will take substantial time. During the thousand-year prophetic period you can ask all your questions and look into all the books, to form a righteous judgment an endorse Gods final say.
Judging a 6000-thousand-year long history, that is quite a job. You could use a thousand years for that for sure. But after this period, it's all good. Everything has been discussed, every pressing question has been asked. This procedure fits with a voluntary covenant of love. All Gods people will be at peace with it and agree wholeheartedly: “Yes, Your judgments are just and trustworthy!” Only then will God carry out His final judgment and start up the new world.
By inserting a thousand-year interval, God sets the tone for His perfect new world. There will be no more sin, dubiety, suspicion, or reproach. It will be a perfect, voluntary, and everlasting covenant of love, which can never be broken again by any lie. The primordial lie — that God's intentions are bad and you're better off taking His place — has been forever robbed of its power, as history has shown us how God has gone to the extreme for us. He is indeed completely good and trustworthy. He will dwell among his people, forever and ever (Revelation 21). By then 'the first things' have passed. The moral foundation for the new heaven and the new earth has been laid. The future is open to live with Him in a kingdom of true and everlasting peace [In the beginning]!