First, let me say that this discussion is for edification. It does not in anyway affect OUR salvation. I have difficulty understanding why sacrifices during the Messianic Kingdom are necessary. However, I love the Lord with all my heart and if He says to make sacrifices, then that's what I would do... Do you understand what I'm saying? Whatever God says do, I will do. The problem I am having is the understanding.
Now, There are lots of references to sacrifices in the Messianic Kingdom. Ezekiel not only gives us the measurements of the Temple, but also identifies the feasts to be celebrated and the sacrifices along with them.
Compare the Levitical Feasts with the Millennial Feasts
L. N/A M. New Year - Ez 45:18-20
L. Passover Lv. 23:5 M. Passover -- Ez 45:21-24
L. Unleavend Bread M. Unleavend Bread
Lv. 23:6-8 M. Ez 45:21-24
L. Pentecost Lv 23:9-2 M. N/A
L. Trumpets Lv. 23:23-25 M. N/A
L. Atonement Lv 23:26-32 M. N/A
L. Tabernacles Lv 23:33-44 M. Tabernacles Ez 45:25 Zech 14:16-21
Feast of the Tabernacles is the "do or die" feast. Every nation absolutely must participate in this feast coming to Jerusalem or the rains will be with held for one year. Which means no food and so forth. We know this is in the Millennium because that had never been a requirement in the Law of Moses. It could not have been practiced after 70AD because the sacrifices were no longer practiced because the Temple had been destroyed. The only time it could be viable is after the new Temple is built.
It is well documented by several Biblical scholars that the prophets had difficulty in knowing the time frame of the prophecy. Their writings aren't chronological so to speak. Daniel is much more chronological and it seems to me that Ezekiel is more chronological, too. Especially in the last verse of the last chapter where the city is named THE LORD IS THERE." v 48:35. Jeremiah reads to me like a scribe dropped a sheaf of papers and hastily scrabbled them together and that’s how the book was preserved.
I think this is why God is so specific towards who will be able to enter the Temple... only the "circumcised of heart" may enter (Ezekiel 44:5-9). That is only believers may worship there and pray there. He admonishes Israel to have no more abominations. Which is a look-back at what the priests did in Solomon's day all the way up to King Herod's day and what they did to Jesus. All through the OT, there is sin everywhere which is the reason that sacrifices were necessary. But the sacrifices offered were abhorrent to God (Malachi 2) they were thrown back in the faces of the priests as offal. In other words, God rejected the offerings of the people of Israel because they turned from Him and became as a harlot for the gods of other nations.
So we have on one side of the cross, blatant stone-hearted people that act a part without being clean on the inside and a few that trusted God to do as promised. And on the other side of the cross we have stone-hearted people that reject the gift of Grace with a few of us very blessed ones that believe in what Jesus did.
Sacrifices were necessary before the cross, but were rejected by God because of the nature of their hearts. The Temple was destroyed, I believe, because of the sheer horrendous nature of an incredibly falling-short sacrifice of animal (bull or lamb) offered to God in rejection of the sacrifice made by God, the Holy Son of God.