It may help our understanding of the passages in Rom. 11 to know that the first allusion to the Church, the body of Christ, in the Epistle to the Romans is in chapter 12, verse 5. Even there we do not find the doctrine of the Church taught, but the practical walk of the members one with another as "one body." It is not the subject of the Epistle to the Romans.
The Apostle in beginning his subject of the olive tree, writes. "I speak to you Gentiles." He does not speak to the Church us such, although his teaching is for the Church. It is the Gentile dispensation which he has before him.
The olive tree symbolizes the line of the testimony and of the promises of God under the figure of a tree. Abraham was the root of that tree as being the depository of the promises. The nation of Israel, his posterity, was the branches—the fatness, the promises of God.
This tree of promise begins in Abraham, and runs on into the Millennium. God always maintains a stock (Christ), and the faithful of any dispensation, which sustains God's testimony in the line of promise on earth. The Jewish dispensation proved itself a failure.
They were the natural branches, and it was their "own olive tree." "Because of unbelief they were broken off." The Gentile dispensation commences, and the wild olive branches are grafted into the stem, and thus brought into the place of testimony and line of promise (to them spiritual), in which they stand "by faith." In such a place they were to continue in the goodness of God, or failing in this to be cut off. God, who did not spare the natural branches, would not spare them. The Gentile dispensation not having continued in the goodness of God, will be cut off. Meanwhile God has His own purposes to fulfill, "and the long-suffering of our Lord is salvation." 2 Peter 3:1515And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you; (2 Peter 3:15). "Blindness in part is happened to Israel, until the fullness of the Gentiles be come in." Then the Jews will be grafted in again, as the natural branches, and thus Israel nationally will be saved—not individually as now.
It is not at all a question of the Church, as the body of Christ, or of individual salvation, but of Jewish and Gentile dispensations, and the result of the failure in each of them. F.G. Patterson