v1-6: God's sovereignty in grace; our part is to accept His will, being subject to Him.
v1: Paul writes as a Jew, saved by the grace of God, sharing the faith of Abraham. He is himself testimony that the Jewish people are not cast off in their entirety.
v2-3: God foreknew His people, and therefore cannot cast them away. We may feel few and isolated, like Elijah, "I alone am left." Or others might think that only Gentiles are being saved.
v4-5: The faithful remnant; in Elijah's day, 7,000 reserved for God. The remnant is according to grace; for each one has found faith in Christ. Even when things are at a low ebb, God is faithful to Himself, and maintains a faithful testimony on earth.
v6: Election is of grace, not of works, it is not earned.
v7-10: Unbelieving Jews were hardened; God used many experiences to do this; famines and droughts, military defeats, exile in Assyria and Babylon; those who did not want God could not have Him.
Israel did not obtain salvation; as a nation they did not seek it on God's terms. Their refusal to submit is a rejection of God. Their rejection is rewarded by a "spirit of stupor," and judgment.
v11-12: Jealousy; the salvation of Gentiles through the church is itself a sign to the Jews. Notice that riches for the Gentiles is a direct consequence of Jewish unbelief.
God's plan is that the Jews see the blessing of God upon Gentiles, and therefore seek God's blessings for themselves. Wonderful things lie ahead for the Jews and, indeed, for the world.
Paul uses the concept of wealth to describe the blessings of salvation, as in 2 Cor 8.9.
v13-14: Although Paul is called specifically to the Gentiles (Acts 9.15; 22.21) he maintains a deep concern for the Jewish people. He realises that his ministry can bring blessing to them also.
v15: Today they are cast away, but one day they will be accepted again.
v16: The first fruits are holy, and the root is holy; therefore all is holy. Since believers are grafted into the Holy One, then we too are holy.
v17: A wild olive is grafted into a fruitless tree to make it bear fruit; the picture is of Gentiles being joined to Christ. The Jews have rejected Him, and, being the natural branches, are broken off. This refers to the nation, rather than to every individual within it, as in v5.
We are partakers of the root, which gives us security. There is "nourishing sap," which is the abundance of the Holy Spirit from the root, which is Christ.
v18-19: No ground for boasting, for we rely upon the root.
v20: We do not boast, for we stand by faith; we cannot be proud of any achievement of ours. We are grateful that God has enabled us to believe.
v21: There is no room for an anti-Jewish attitude, for the Jewish people are the natural branches, see also v25.
v22: The on-going choice; receive either God's goodness or His severity; John 15.6. We are not to be complacent, nor presumptuous. Rather we must maintain a close relationship with God.
v23-24: There is a logic that the Jewish people will be grafted in again; this is truth, not just Paul's wishful thinking. Natural branches are grafted in again to enjoy renewed fruitfulness, and to encourage further fruitfulness.
v25: Israel is hardened; in part, not totally; until ... , not forever. The position in Paul's day, he insists, is not the whole story. Thus the Jewish people do have a future in the plans of God.
There is a full number of the Gentiles; a great multitude of every people, nation, tribe and tongue.
v26-27: One day all Israel will be saved, when Christ the deliverer comes, being revealed from Zion. He will take away their sins, in accordance with His promise, and he new covenant with them.
v28-29: Whilst Paul witnesses Jewish opposition to the gospel, there remains God's calling which is irrevocable.
v30-32: The marvellous truth of God's mercy, which falls on the disobedient. In contrast, His wrath falls on the unbelieving. See also 4.5; He justifies the ungodly. This is a reminder that none deserve the great blessings of God in Christ.
v33-36: Paul's conclusion; we cannot fully understand God's ways. We may be tempted to reduce Gods' word to a future timetable of human speculation concerning Israel, the church, and the world; the proper response is to worship Him and to trust Him. We are confident that the glory of God will be manifest in the gospel being proclaimed, and changing many lives. Where the purposes of God eclipse human reason, we rest in His perfect justice.
Paul, as elsewhere, uses a series of OT verses to enforce his teaching. These words are God's, spoken through Isaiah and Job; but here they are a doxology of praise to God.