There is no clear reason given for the length of one thousand years, but that is plenty of time to fill the earth with people. And it will be a very different place. The animal world will be at peace, with previous predators and prey playing together like friends. People will once again live for hundreds of years. It will be similar to the Eden experience, but with at least one glaring distinction: man’s heart.
It will still be fallen and naturally unholy. There may not be any prohibited trees around to tempt them, but there will be plenty of moral rules to abide by, all under Christ’s perfect eye of justice. For ten centuries the world will be policed by a benevolent Master, who rewards all evil and good with exactly what they deserve.
And yet, in spite of this ideal situation, many will be itching for freedom to do as they please. They will chafe, even under the kind hand of the King, and wish they could be completely autonomous and answer to nobody. All that is needed for man to organize a rebellion and show his cards will be for them to have a specially powerful and sinister leader.
Yes, the Serpent will be released, to once again do his nasty will. He has plenty of energy and takes off on a global campaign to mount an almost universal revolution against the Lord. He knows his doom, but is bent on destroying as many humans as possible in his last strike. They are referred to as Gog and Magog, which seems to be another Biblical example of taking ancient places and people, and attributing to them representative, prophetic significance. Maybe they see themselves as the rightful heirs and victorious descendants of Cain and his clan. At any rate, they join to form a number as large as the sands of the earth’s shores. Their strategy is to attack and destroy the King’s beloved city and its surroundings, from where He rules the world in perfect love. Nothing but fair laws and excellent government has ever come from that capital city. But they are inflamed with pride and blind to all good reason. It is an ugly story.
But the that’s not the end. Better things are ahead!
7 And when the thousand years are expired, Satan shall be loosed out of his prison,
8 And shall go out to deceive the nations which are in the four quarters of the earth, Gog, and Magog, to gather them together to battle: the number of whom is as the sand of the sea.
9 And they went up on the breadth of the earth, and compassed the camp of the saints about, and the beloved city:
Because the Holy Scriptures are of divine origin, we should not be surprised to discover marvelous harmony underneath the surface and between items that seemingly have nothing to do with each other. What an amazing Book! What an amazing God!