Isaiah 66:23 predicts that, in the new heavens and the new earth, all flesh will worship God on the Sabbath. Sabbatarians appeal to this passage to argue that the Sabbath is an eternal (not a temporary) institution. According to the context of Isaiah 66, this event will occur after Israel's restoration to her land, which will be followed by a time of paradise. Other passages indicate that the Levitical priesthood, a physical sanctuary, animal sacrifices, and the Feast of Tabernacles will also be in effect at this time (Jeremiah 33:18-22; Ezekiel 43:20, 26; 45:15, 17, 20, 22; Zechariah 14:16-19).
This set-up seems to conflict with certain New Testament passages, which treat the Levitical priesthood and animal sacrifices as temporary shadows of Christ (e.g., Hebrews 7-10). As we saw in Eschatological Sabbath: The Spiritual Interpretation, there are many Christians who interpret those Old Testament texts spiritually, not literally. That's their solution to this whole dilemma!
But there are other Christians who maintain that the texts will have a literal fulfillment. They're called dispensationalists, and they believe that Christ will return to earth as Israel's Messiah, rule for a millennium, and set up a new temple with real-life animal sacrifices, some of them for atonement (Ezekiel 43; 45). How do they reconcile this belief with the Christian idea that Jesus was the ultimate sacrifice for sin, thereby rendering animal sacrifices unnecessary?
Many dispensationalists maintain that the millennial sacrifices will be commemorative, not effective for atonement. For them, they'll celebrate the fact that Christ died for people's sins, but they won't have atoning power in themselves. When someone points out to them the verses in Ezekiel 43 and 45 that claim the sacrifices indeed will make atonement, they have a come-back. They argue that Leviticus 4 and II Chronicles 29:23-24 also say that Israel's sin offerings atoned for sins, yet we know from Hebrews 10:4 that such was not the case. In same way that the sin offerings before Christ's coming were said to atone for sin but did not really do so, they contend, the future sacrifices of Ezekiel's temple will be "for atonement," even though they'll lack inherent atoning power. One dispensationalist lady called this "commemorative atonement." Clear as mud?
Other dispensationalists say that the millennial sin offerings will take care of sin, at least on a temporary basis. For them, the sacrifices will sweep people's sins under the rug in order to appease a just God, but they won't be totally effective, since they'll have to be offered more than once (see Hebrews 10:1-4). In this view, the sin offerings aren't as powerful as the sacrifice of Christ, but they do have some atoning value.
In any case, dispensationists think that the Old Testament law will be in force in the millennium. I once visited a Bible study at a Sunday-keeping church, and a meek little woman was asking about the Sabbath. "Why don't we keep Saturday?," she asked. "It's part of God's law! 'Remember the Sabbath day' is in the ten commandments." One of the other members (a know-it-all when it came to the Bible) had an answer: "Right now, we're under grace. When Christ comes back, we'll be back under the law again." I thought that sounded pretty absurd at the time, but I realize now what he was trying to do. He had to reconcile the different parts of Scripture in some way, and his approach was a good-faith effort.
Interestingly, Armstrongites embrace a dispensationalist approach in parts of their eschatology. They believe that Jesus Christ will return to earth and rule for a thousand years. I've heard Ron Dart interpret Ezekiel's temple in a literal sense. Sometimes, he acts like we'll have animal sacrifices because the law is still binding--all of it. I vaguely recall him saying that a big reason we don't do animal sacrifices right now is that there isn't a temple in Jerusalem, the only place one can legally offer them. (But this is from my fallible memory.)
At other times, however, Dart treats the millennial sacrifices as pedagogical, in that they will serve to teach people about God. And what better way is there to instruct people about Christ's sacrifice than to slaughter an animal right before their eyes? As Dart said in a sermon, that graphically conveyed to a person the severity of his sin! It screamed, "This animal should have been you, but, fortunately, you've got a substitute!"
I have a hard time with what that one Sunday-keeper said: Now, we're under grace, but we'll go back to being under the law once Christ returns. That presents God as so arbitrary! "Oh, you're in this category, but I'll move you here, and then I'll put you back into your original category when I so desire." Why would God herd people like rabbits?
So there has to be a reason that God will put people under the law in the millennium (assuming we should go with a literal interpretation of the Old Testament prophecies). And I think that the pedagogical explanation is pretty good.
In the millennium and hereafter, God will be teaching people who do not know him: both Jews and Gentiles (Isaiah 2:3; 30:20). To do that, he'll have to give them structure, which Sabbaths, holy days, and animal sacrifices provide. People are visual creatures. They need rituals to hold on to. They benefit from things they can do and see. The way the Old Testament presents the Egyptians, for example, they assumed that the Nile was their creation (Ezekiel 29:3). God can tell them that it's not, but what will that accomplish? It's better to show them--to give them a ritual in which they can concretely acknowledge God's provision for them. And what better way is there to do that than to make them keep the Feast of Tabernacles, a water festival, while depriving them of the Nile if they did not do so (Zechariah 14:16-19)?
Eventually, however, one needs to graduate to the next level. People can learn basic concepts about Jesus from the Sabbaths, the holy days, and the animal sacrifices, but they eventually need to focus on Christ instead of the rituals that point to him. As the KJV of Galatians 3:24-25 puts it: "Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith. But after that faith is come, we are no longer under a schoolmaster." In the same way that the Torah prepared Israel for faith in Christ, so also will the millennial Sabbaths, festivals, and sacrifices do this for people who don't know God. But they're temporary institutions in this scenario (or possibly they are), with a specific objective for their existence.
But I have questions even about this scenario. For example, why didn't the Gentiles in New Testament times have to obey the laws regarding the Sabbath, holy days, and animal sacrifices? They didn't know much about God when they became Christians, did they? Why were they able to bypass the schoolmaster as they went on to spiritual maturity?
Maybe the answer is that they already knew things about God before their conversions, since there were Jews in the Diaspora who could teach them. Perhaps, but isn't our culture saturated with the Bible? Even non-believers know things about it! If Christ's coming is soon, why would they need to go through a millennial elementary school in order to learn the basics of Christianity? But what's true now may not always be the case. Perhaps the time before the Second Advent will be one of gross spiritual ignorance, so people will need to learn the basics during Christ's millennial reign.
It's something to think about!