Q. What will happen to the resurrected martyrs from the Trib who live in the 1000 Yr Kingdom? Will they die again, Or just the “regular 1000 year humans”? Where do those humans come from, and how will they achieve 1000 year life spans?
A. Tribulation martyrs who are resurrected at the 2nd coming will not die again. After the Millennium, they will go into eternity with other resurrected beings.
The sheep and goat judgment (Matt. 25:31-46) will take place just after the 2nd coming for humans who survive the Great Tribulation. The believers among them will go into the millennium in their natural state and help repopulate Earth (Matt. 25:34).
Isaiah 65:20 makes reference to increased human lifespans during the millennium. I believe they will begin to approximate the lifespans of pre-flood humans again because the curse will be removed from earth (Rev.22:3) which in my opinion will include the return of the water vapor canopy that surrounded Earth before the flood and prevented the contamination of the human cell regeneration process.
I also believe millennial mortals will be judged at the end of the 1,000 years along with the unsaved of all ages. Why else would John say that anyone whose name was not found in the book of life would be thrown in the lake of fire (Rev. 20:15)? None of the unsaved will be found in the book of life so there must be some in that judgment whose names do appear there. These can only be the saved from the millennium.