'Olive tree' in the Bible
But some of the branches [of a cultivated olive tree] were broken off [i.e., God's rejection of the Jews] and you [Gentiles], representing a wild olive tree [branch], were grafted into it. So then, you [Gentiles] were able to benefit from the roots and sap of the olive tree, along with the Jews.
And these Jews also will be grafted [back] in [to the olive tree] if they do not continue in their lack of faith [in Christ], because God is able to graft them back in again.
For you [Gentiles] were cut off from a natural wild olive tree and [then], contrary to the natural process, were grafted into a cultivated olive tree. [Since that has happened], how much more likely is it for these [Jews], who are the natural branches, to be grafted [back] into their own olive tree [again]?