What kind of tree is a wild olive tree — does it bear fruit?
The wild olive tree is portrayed as worthless and unfruitful, producing no fruit and likened to a bad weed. In this illustration, Gentiles are the wild olive tree grafted into Israel, the good olive tree, so they partake of the root and fatness rather than contributing fruit of their own.
Les explains that Romans 11 uses grafting as an illustration. Gentiles are the wild olive tree grafted into Israel, the good olive tree, so they share the root and fatness. He notes this reverses normal grafting: normally a native root is kept and a good hybrid grafted in, but here the good tree is cast aside and a wild olive is grafted in. The wild olive, as he understands it, produced no fruit and was worthless, like a bad weed. He clarifies the grafting speaks of the whole Gentile system, not only believers, being brought into what was originally Israel. That root traces to Abraham and Genesis 12:3, where God promised all families of the earth would be blessed, a promise never abrogated.
And if some of the branches be broken off, and thou, being a wild olive tree, wert graffed in among them, and with them partakest of the root and fatness of the olive tree;