Romans 11:17

The cultivated olive tree was a symbol of the nation of Israel in the Old Testament (Jeremiah 11:16-17; Hosea 14:4-6). The wild olive tree represents the Gentile world. [Note: Bruce, p. 204.] The rich root of the cultivated tree, Israel, probably corresponds to the Abrahamic Covenant from which all God’s blessings and the very life of the nation sprang. We might add to the illustration by saying that the roots derive their nourishment from God Himself.

Paul said that God grafted Gentiles in among the Jews. They became partakers with the Jews of the blessings that come through the roots. Paul did not say that the Gentiles became part of Israel, only that they partake with Israel of the blessings of the root. This is a very important point. The olive tree is not the church, the "new Israel," in which God has united Jewish and Gentile believers in one body (Ephesians 3:6). The wild olive branches retain their own identity as wild branches (Gentiles) even though they benefit from blessings that come through Israel (e.g., the Messiah, the Scriptures, etc.).

A common misunderstanding of this figure is that the olive tree is a symbol of all believers throughout history, all the people of God. The natural branches, in this view, represent Israel, and the grafted in branches represent the church. The Old Testament use of the olive tree as a symbol of the nation of Israel argues against this view. Furthermore this verse says some of the natural olive branches (Israelites, according to this view) were broken off the tree. If the tree represents all believers, this must mean that some believing Israelites have ceased to be part of the people of God.