It seems to be becoming increasingly popular amongst many Christians nowadays to celebrate Jewish feasts and holidays. There is also a common belief among many Christians that during a future Millennium God will again be expecting everyone to keep the Jewish feasts. Even more common is the belief that God intends to refocus His attention on Israel during a future period of great tribulation.
The Gospel truth is that all Christians whether Jew or Gentile are free from all obligation to keep Jewish rituals both now and forever. God isn't focusing His attention on Israelis any less right now than He will at any time in future. God will never again be expecting anyone to resume keeping Jewish rituals – not even the Jews – not at any time in the future.
Jesus is everything; He is enough for all, whether Jew or Gentile – and forever will be enough. And not only is He enough, but He is the only thing that will ever be of any consequence.
Paul wrote that Jewish rituals in themselves have no merit. Only Christ has merit. Therefore Paul asserted that we believers needn't feel obligated to observe Jewish feasts and special days at all. We all are forever free.
Paul described a believer who feels he still needs to observe external obligations as being weaker in faith. Strong faith assures us that we don't need to observe such things.
But Paul added that the believer who observes such externals and the believer who doesn't, are both honouring the Lord with their conscience, therefore both should tolerate the other.
In other words, if you feel you need to observe certain external obligations, I shouldn't make a divisive issue out of it. Go for it, if you feel you need to. But on the other hand, I needn't allow you to make me feel obligated to keep it either. The reason being: you don't really need to observe such things either.
Part of the reason for this tendancy amongst many believers today is a misunderstanding of the Bible verse which said that certain rituals were to be statutes forever in Israel. "Forever" simply meant, for as long as the Old Covenant still stood. It was never intended to literally mean forever.
Another reason is the misapplication of Old Testament prophecies. Any Old Testament prophecies which spoke about Israel again keeping the Levitical functions won't be fulfilled during some future Millennium or tribulation – they were already fulfilled while the Old Covenant still stood, many of them when Israel returned from captivity in Babylon.
The salvation promised to the Jews is not awaiting a future fulfilment – it is being experienced right now by believing Jews. Rather then awaiting a future fulfilment of such promises, Paul explained the manner in which the promises were already being experienced – they were being experienced in the lives of Jewish believers, and the Gentiles also were partaking of it. Paul wasn't awaiting the fulfilment of such promises during a future tribulation or Millennium. He explained how it was being fulfilled now.
It was being fulfilled by the Church – both Jew and Gentile.
Paul showed that the Prophets themselves foresaw this outcome. This was Paul's revelation. Paul wasn't awaiting the future fulfilment of such passages.
Misapplying these Scriptures of the Prophets has become the basis for a lot of fanciful modern ideas about the place for Old Covenant ritual during a future tribulation and during the one thousand years.
Paul's revelation instead was that the Gospel fulfills prophecy therefore we are all free forever.