We often hear Christians say that they are "grafted onto the Tree of Israel." Certainly the historic Yeshua ben Miriam (Jesus, son of Mary) was Jewish and doubtless mainly Torah observant. Believing themselves to be the spiritual heirs of his proposed reforms they cite Paul in order to give support to their place in biblical religion and as the spiritual descendants of Avraham Avinu. This is the point of Paul's analogy.
Here is the section of their writings that discusses this idea.
Romans 11:1,2 I [Paul] say then, has God rejected His people? God forbid! For I also am an Israelite, a descendant of Abraham, of the tribe of Benjamin. God has not rejected His people whom He foreknew...
11:11 I say then, have they stumbled that they should fall? God forbid!...
11:17 But if some of the branches were broken off, and you, being a wild olive shoot, were grafted in among them and became a partaker with them of the root and richness of the olive tree,
18 do not boast against the branches. If you boast, remember you do not sustain the root, but the root sustains you.
Paul believed, according to his opinion as a follower of Yeshua, that the Jewish authorities had erred in their rejection of Yeshua's proposed reforms. We wont debate this point in the present study. I have a lot material on that question elsewhere on the site. For now, let's focus on the tree analogy.
Paul is clear that HaShem has not rejected the Jewish people nor the Covenant (verses 1,2). He is also clear that God "foreknew" the Jewish rejection of Yeshua (verse 2)
and maintains the Covenant with them anyway. So without contradicting these statements of Paul one can not defend the notion that Jews must accept Jesus in order to be accepted by God, or in Christian parlance, "be saved."
Likewise Paul says: ... you do not sustain the root, but the root sustains you. So the foundation of the "tree" is not Jesus according to Paul, it remained in his generation the Sinai Covenant revealed in the Torah (the Law) with the Jewish people (the "tree") as it has been since the days of Avraham and Moshe. By the 3rd century CE the Christian Church had completely severed itself from Judaism. Since the nourishment of the "root" (the Sinai Covenant) passes to the "grafted on branches" through the "tree" (Judaism), the Christian religion had self-removed itself from all ties with the Jewish "tree" and its "root." What the Church termed "Judaizing" was declared illegal. Therefore, without the rabbis leadership from the Torah roots. since the 3rd century CE at the latest, Christianity has existed as a completely separate religion from Judaism, with roots in Rome and Constantinople rather than in Jerusalem.
Missionary Christian claims that Jews need to leave the "tree" and embrace the "grafted on branch" obviously contradicts this clear teaching of Paul. Again, "... you do not sustain the root, but the root sustains you." That was arguably the case in Paul's time but post Constantine it no longer is. To try and convert a Jew is like standing on a tree limb while cutting it from the tree. Were all the Jews to "accept Jesus" the "tree" would cease to exist. Without the "tree" the branches would quickly wither and die.
To say that the Torah (the Law) was "nailed to the cross" places the branches above the tree in defiance of Paul's doctrine. To say that Jesus was god incarnation places the New Testament above the Sinai/Torah "root" and that contradicts not only Romans eleven but Jesus himself:
Matthew 5:18 For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law [the Torah], till all be fulfilled.
For further study:LearnEmunah.com
Isaiah 7:14 in Context: Almah and the virgin birth
Unto us a son... Understanding Isaiah 9:5,6
The "Suffering Servant": Is Isaiah 52-54 about Jesus?
Zechariah 12 Is this a prophecy about Jesus? No.
Micah 5 Is this a prophecy about Jesus? No.
Before Abraham was I Am: What did Y'shua mean with this statement
What The Messiah Must Accomplish: Did Jesus Meet the Qualifications?
The Nicean Creed: The Anti-Torah Foundation of Christianity
Etc.
BeitEmunah.com
AllFaith.com in Exile
Christianity Pages
And
Don't let the perfect defeat the good