17 And if some of the branches were broken off, and you, being a wild olive tree, were grafted in among them, and with them became a partaker of the root and fatness of the olive tree,
Verses 17 to 24 expand the olive tree’s root-and-branches illustration (v. 16). These verses also contrast both natural and wild branches. Verses 17 and 18 argue that Gentile believers should not brag about the cutting off of the branch of unregenerate Israel. This verse sets forth a contrast between believing Israel, unbelieving Israel, and Gentile believers.
17 And if [since] some [not all] of the branches were broken off [unbelieving Israel],
In the illustration the olive tree is the unregenerate nation of Israel as a whole. God put aside Paul’s generation of Jews, for the most part, except for the remnant who believed in Jesus the Messiah. The reason was that Israel rejected the grace provision of the Messiah.
Not all Jews were broken off from the tree, for “some” were not. Only unbelieving Jews—those who rejected the Messiah—were cut off.
and you [singular],
Paul spoke here to Gentiles as a unit in the Roman church.
being a wild olive tree [shoot],
Roman Christians were Gentiles who were not part of the nation Israel, the cultivated olive tree. The “wild olive tree,” then, is a representation of Gentile (non-Jewish) believers. The reason God broke off the natural branch of Jews is to graft into the tree Gentile believers.
were grafted in among them,
God grafted wild branches of Gentiles into the olive tree, the regular cultivated olive tree of Jews. Gentiles are grafted into the tree by faith. This was not a natural process (v. 24).
God set aside the theocratic kingdom of Israel and grafted both Jews and Gentiles into His new plan (the church). Thus, God’s plans for the nation Israel and the church are distinct. The grafting in here is the launch of the church.
and with them became a partaker of the root and fatness of the olive tree,
The Old Testament describes Israel as an olive tree (Jer 11:16-19; Hos 14:6-7). Thus, the olive tree here is ethnic or national Israel. Christians are indebted to Israel who sent the Messiah for their salvation. Believers are now part of the people of God composed of both Jews and Gentiles.
The word “fatness” may refer to nourishing sap of the olive tree. All believers draw on the Abrahamic Covenant for blessing.
John 4:22, You worship what you do not know; we know what we worship, for salvation is of the Jews.
Ga 3:14, that the blessing of Abraham might come upon the Gentiles in Christ Jesus, that we might receive the promise of the Spirit through faith.
God supernaturally connected Gentiles to the family of God. He grafted Gentiles into Israel’s blessing; that is, they partook of the blessings of Israel through the “root.” The “root” was the Abrahamic Covenant.
This does not mean that Gentiles during Paul’s day became part of Israel, but only that they partook of the blessings of Israel. Both the natural branches and the wild branches retain their identity.
We gain status with God by grace provision.
The breaking off of unbelieving Israel and grafting in of believing Gentiles represents positional truth, the believer’s status with God. The only way they can gain this status is by grace; that is, God of His own initiative providing the resources through Christ. Both Jew and Gentile have this privilege in the church.