In Romans 11, Paul speaks of the cultivated olive tree, and that there are natural branches (physical Jews), but many of those have been broken off (because of unbelief), and then there are branches from a wild tree (physical Gentiles) that are grafted onto the cultivated tree.
What is the cultivated olive tree? Well, an olive tree produces olives, and olives, when crushed, produce olive oil, and olive oil is a symbol of the Holy Spirit. So, the cultivated olive tree has branches that are part of the tree, and are fed by it, which means they are of the Holy Spirit (indwelt by Him). All the branches, whether natural or grafted on, are a part of the same tree.
The cultivated olive tree is Y’isra-el, and Y’isra-el is made up of those who have the new covenant, which is the seal of the Holy Spirit upon Messiah’s bride. As Paul explained in Romans 2:29, the true Jew is not a Jew because of anything physical or outward, but is so because of a circumcised heart, which means that the true Jew is anyone who is indwelt by the Holy Spirit.
Now, christianity came along (codified in the 4th century), and rejected the Father’s traditions, and invented its own path to salvation, which is nothing more than a human decision pumped up with a bunch of feelings.
The perverted mindset that comes from the false teachings of christianity is that the cultivated olive tree became a wild tree when some branches from the wild tree were grafted onto it. That is ludicrous. When the branches from the wild tree are grafted onto the cultivated tree, the branches become a PART OF THE ORIGINAL TREE! The tree doesn’t change what it is—the new branches that were grafted on do.
So, this notion that the Father’s traditions apply only to the physical Jews (most of whom were branches that were broken off because of unbelief), and that the olive tree became the “church” or “christianity” is absurd.
No, those who have been grafted onto the cultivated olive tree are made a part of Y’isra-el, and the branches of Y’isra-el are called “Jews.”
One is either a Jew in the Father’s eyes, or he is not a Jew. Christianity being a counterfeit of the true faith, one cannot be both a Jew and a christian. Being a christian simply means that one has chosen to be an adherent of a counterfeit. One cannot be a part of the genuine tree (Y’isra-el) AND a part of the counterfeit of that tree (christianity). It’s not possible.
I am a true Jew by adoption (justification) and by marriage (covenant), so I cannot be a christian. I must be that which my adoptive Father is. And, since Messiah is a Jew, His bride MUST also be a Jew.
The Father’s Sabbaths are a sign between Him and His true children—they are a family identification for those who have been made a part of the family tree, the cultivated olive tree, Y’isra-el.
For more information: Circumcision and Spiritual Reproduction