It is as if some of the branches from an olive tree have been broken off, and the branch of a wild olive tree has been joined to that first tree. If you are not a Jew, you are the same as that wild branch, and you now share the strength and life of the first tree.
It is not natural for a wild branch to become part of a good tree. But you non-Jewish people are like a branch cut from a wild olive tree. And you were joined to a good olive tree. But those Jews are like a branch that grew from the good tree. So surely they can be joined to their own tree again.
Remember your Creator while you are young, before the silver rope snaps and the golden bowl is crushed like a jar broken at the well, like a stone cover on a well that breaks and falls in.