Christ is not the olive tree! He is the root of the tree that the tree derives it's life.
The tree is Israel, the branches of the tree, and we Gentiles, only by the Grace of God, are grafted into that tree with Israel, the natural branches.
Gentile believers are grafted in with Israelite believers. Israelite unbelievers were cut off.
Romans 11:17 If
some of the branches have been broken off, and you, though a wild olive shoot, have been grafted in among the others and now share in the nourishing sap from the olive root, 18 do not consider yourself to be superior to those other branches. If you do, consider this: You do not support the root, but the root supports you. 19 You will say then, “
Branches were broken off so that I could be grafted in.” 20 Granted.
But they were broken off because of unbelief, and you stand by faith. Do not be arrogant, but tremble. 21 For if God did not spare the natural branches, he will not spare you either.
You seem to act as if all of Israel is part of the olive tree, but it's only believers who are in it, as is the case for Gentiles as well.
We Gentiles are the inferior branches of the tree.
Where is this taught? Scripture says there is neither Jew nor Gentiles and that we are all one in Christ (Galatians 3:26-29). It does not teach that anyone is inferior.
This means that God called Israel to introduce Christ to the world. He gave the Law to them, not the Church. He gave them the womb of the Christ, not the Church.
We are second, they were first. This is revealed when Christ said the "first shall be last, and the last first."
Israel was called first, but will be the last saved, The Church was called last/second choice, but will be the first saved.
Casting away Israel is contrary to the writing of Paul. He said they are not cast away, but have been placed in temporary blindness until the Gentiles are saved. Then God will call on Israel again, and this time they will not fail. They will fulfill their calling, but it will be during the 1000 year reign of Christ when they do it.
There have been many Israelites that God has called to salvation and that have been saved after hearing the gospel for the past almost 2,000 years now. Why do you act as if God has postponed their salvation? There were 3,000 of them saved on the day of Pentecost alone, so their salvation was never postponed.