I'd suggest reading all of Zachariah, and Eze, Chapters 40-49, Isa, Chapters 2-4-10-11, will give you an idea of what the conditions will be during the Mill reign.
Finally, we get an answer to the question of how one is saved during the Millennium. The answer is found in EZE 40-47 according to dispies. Apparently the blood of Jesus is no longer sufficient for a sin offering. No, we must go back to the types and shadows of the Old Covenant. Remember, the services the writer of Hebrews says God has no pleasure in:
Heb 10:6
In burnt offerings and sacrifices for sin thou hast had no pleasure .
Heb 10:7 Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God.
Heb 10:8 Above when he said,
Sacrifice and offering and burnt offerings and offering for sin thou wouldest not, neither hadst pleasure therein; which are offered by the law; Heb 10:9 Then said he, Lo, I come to do thy will, O God.
He taketh away the first, that he may establish the second .
Yes, take away the first so that He may establish the second, then of course go back to the first. Is this about how it is? Well, a “literal” reading of Eze 40-47 tells us offerings are made for sin:
Eze 40:39 And in the porch of the gate were two tables on this side, and two tables on that side, to slay thereon the burnt offering and the
sin offering and the trespass offering.
Eze 42:13 Then said he unto me, The north chambers and the south chambers, which are before the separate place, they be holy chambers, where the priests that approach unto the LORD shall eat the most holy things: there shall they lay the most holy things, and the meat offering,
and the sin offering , and the trespass offering; for the place is holy.
Eze 43:19 And thou shalt give to the priests the Levites that be of the seed of Zadok, which approach unto me, to minister unto me, saith the Lord GOD,
a young bullock for a sin offering .
Eze 45:17 And it shall be the prince's part to give burnt offerings, and meat offerings, and drink offerings, in the feasts, and in the new moons, and in the sabbaths, in all solemnities of the house of Israel:
he shall prepare the sin offering, and the meat offering, and the burnt offering, and the peace offerings, to make reconciliation for the house of Israel.
Eze 45:18 Thus saith the Lord GOD; In the first month, in the first day of the month, thou shalt take a young bullock without blemish, and cleanse the sanctuary:
Eze 45:19 And
the priest shall take of the blood of the sin offering , and put it upon the posts of the house, and upon the four corners of the settle of the altar, and upon the posts of the gate of the inner court.
Eze 46:20 Then said he unto me, This is the place where the priests shall boil the trespass offering
and the sin offering , where they shall bake the meat offering; that they bear them not out into the utter court, to sanctify the people.
There is your answer Old Regular, back to the types and shadows for sin offerings. Sounds like a great time doesn’t it?