For those who enter the Millennial Kingdom still in "human form", when will they receive their new bodies?
The timing of the resurrection of Millennial saints is one of the most challenging questions in scripture, because the Bible does not clearly address this moment. Therefore, we must assume one of two possibilities may be true. Either a Millennial saint receives a new body in a “rapture-like" moment when they turn 100, as suggested by Isaiah 65:20:
Is. 65:20 “No longer will there be in it an infant who lives but a few days,
Or an old man who does not live out his days;
For the youth will die at the age of one hundred
And the one who does not reach the age of one hundred
Will be thought accursed.
Or, a second possibility is that Millennial saints remain alive in their natural bodies through the end of the Millennial Kingdom and are then resurrected at the conclusion of the Millennial Kingdom, as suggested by Revelation 20:4-6
Rev. 20:4 Then I saw thrones, and they sat on them, and judgment was given to them. And I saw the souls of those who had been beheaded because of their testimony of Jesus and because of the word of God, and those who had not worshiped the beast or his image, and had not received the mark on their forehead and on their hand; and they came to life and reigned with Christ for a thousand years.
Rev. 20:5 The rest of the dead did not come to life until the thousand years were completed. This is the first resurrection.
Rev. 20:6 Blessed and holy is the one who has a part in the first resurrection; over these the second death has no power, but they will be priests of God and of Christ and will reign with Him for a thousand years.
According to v.5, the “rest of the dead” come to life when the 1,000 years are complete, thus putting an end to the “First Resurrection” which is reserved for the saints. Following the end of the Kingdom, the Second Resurrection takes place when all unbelievers are resurrected.
Of these two possibilities, we prefer the second option that when a Kingdom saint dies, the body returns to dust while the spirit is taken to Heaven to await resurrection at the conclusion of the Millennial Kingdom.