The Last Great Day represents the great White Throne Judgment, a time when most of mankind that has lived and died during the six thousand year age of man is resurrected back to physical life. Those in that resurrection will have their first opportunity to learn the truth without Satan around to deceive them. They can then choose to accept God's way of life and gift of eternal life or to reject it.
But this post is not about the Last Great Day. It is about the Millennium.
The general resurrection is described in Ezekiel chapter 37. "Again He said to me, 'Prophesy to these bones, and say to them, "O dry bones, hear the word of the Lord! Thus says the Lord God to these bones: 'Surely I will cause breath to enter into you, and you shall live. I will put sinews on you and bring flesh upon you, cover you with skin and put breath in you; and you shall live. Then you shall know that I am the Lord.' " ' So I prophesied as I was commanded; and as I prophesied, there was a noise, and suddenly a rattling; and the bones came together, bone to bone. Indeed, as I looked, the sinews and the flesh came upon them, and the skin covered them over; but there was no breath in them. Also He said to me, 'Prophesy to the breath, prophesy, son of man, and say to the breath, "Thus says the Lord God: 'come from the four winds, O breath, and breathe on these slain, that they may live.' " ' So I prophesied as He commanded me, and breath came into them, and they lived, and stood upon their feet, an exceedingly great army" (Ezekiel 37:4-10).
How many people have lived and died in the earth since mankind began? There are about six or seven billion people alive today. Perhaps there will be 20 or 30 billion or more in that resurrection.
Think about their physical needs!
What will they wear? What will they eat? Where will they live? How will they find homes? All the physical possessions they had in their former life will be gone. Will they have to start from scratch, living in poverty and squalor until they can build up farms for themselves? I don't think so.
God could miraculously provide everything. But it seems that God uses His servants including physical human beings to do what we can to do His work.
Isn't it likely that preparing for these people will be a job for mankind in the Millennium?
Clothing will have to be produced. Food will have to be saved and stored. Housing will have to be built. There are many things that will have to be done to prepare for the arrival of 20 billion or more human beings who will have nothing and will need everything.
There will be a lot of work during the Millennium to prepare for the White Throne Judgment period. But this work will actually be good for mankind in the Millennium.
God's way of life is the give way, the way of love and service towards others, and we learn by doing. Just as the Church learns to put into practice the law of love by working to bring the gospel message and the Ezekiel warning to the world now, so people in the Millennium will have the opportunity to practice the way of love by working to prepare to provide the necessities of life to those who come up in the general resurrection that follows.
Here are links to related sections in Preaching the Gospel:
The Last Great Day - the White Throne Judgment, Chapter 2