So if a new temple gets built the animal sacrifices are going to start up again?
Yes, that is what the bible states, at least, there is enough evidence to suggest that at some point this will happen. But before casting me off as some heretic, let me share a thought, please?
First of all, if and when they resume, I don't believe we will be doing them unless ONLY as a memorial in the same manner communion is done. However, I don't personally go there... I don't see the need for us to take the life of an animal for only a picture. Of course, the animals are not wasted, they are eaten by the priests (and in the case of the Pesach, the Passover, by the family that brought it in) but still...
Secondly, the sacrifices pointed to Yeshua's work. Now keep in mind, sacrifices were for different reasons, not all sacrifices are sin sacrifices after all. But they were done long ago
pointing forward to him and the work he would do and when and if they happen again, they will simply
point back to what he did which leads me to...
Finally... when we get to the Millennial Kingdom, there will be unperfected people alive, the nations will exist. Revelation speaks of us reigning with Messiah and to reign one needs others to reign over. Zechariah speaks of the nations coming to Jerusalem and worshiping the King (Yeshua) during Sukkot (Tabernacles) and if they don't they will be punished in the form of no rain on their crops. I believe it will be THEM who we will be teaching, reigning over, and taking Torah to (God's instructions) and when THEY come to Jerusalem for the Feasts, they will do the sacrifices and learn of Yeshua's work... but also perhaps have a chance to actually see him while there.
What I have just shared does give an answer to something of a conundrum for Christians, the fact that Aaronic Priesthood is called everlasting (in the verse below and two others)....
Exodus 40:15 You shall anoint them, as you anointed their father, that they may minister to Me as priests;
for their anointing shall surely be an everlasting priesthood throughout their generations."
Blessings.
Ken