"May the God of hope fill you with all joy and peace in believing, so that you may abound in hope by the power of the Holy Spirit" (Romans 15:13).
To the question "Has God rejected his people?" Paul points out that a minority or remnant like Paul himself had come to faith. God has a place for individuals to look to the power of the Spirit in a nation which has turned away from God, or not yet turned to God. Even in the dark days when Israel turned to Baal worship God knew that Elijah and seven thousand others were looking to him in faith.
There is therefore both an individual hope and the hope that a nation as a nation can be blessed by turning to God. And if in Paul's day the stumbling of Israel as a nation excluded them so that other nations could come in, Israel could again be restored. We need not try to guess what percentage of a nation needs to turn to God for the whole nation to be blessed by the believers among them. A good start is when churches have been planted in every city (Romans 15:19).
Paul illustrates the national implications of being cut off or being grafted in by the image of faithful Israel as a branch in an olive tree. People of other nations could be grafted in by faith and excluded by apostasy. Similarly Israel, having cut itself off by rejecting the Messiah, could again be restored to the olive tree of faith. And Paul certainly looks forward to this glorious outcome for his own nation.
11:1 Paul is a true Jew descended from Abraham and the tribe of Benjamin. Though a majority of his nation have turned away, he himself has accepted Jesus as Messiah and he lives by the power of the Holy Spirit (15:13, 19).
11:2-4 Even after the great victory on Mount Carmel Elijah had imagined that he alone was left, but he was assured that although the nation had turned to Baal worship, seven thousand still looked to God in faith (1 Kings 19:14, 18).
11:5-6 The believing minority or remnant are those who are "chosen by grace," and as we have seen throughout the epistle grace is the opposite of trying to perfect oneself by "human will or exertion" (5:20-21; 9:16). Faith is looking to the power of God, as Abraham and Elijah did. Since the incarnation, death and resurrection of the Son of God we can focus our faith more clearly on him as Messiah, and allow the Holy Spirit to do his work in us. When we do this we experience the grace of God.
11:7-10 A failure to turn to God's power results in a nation's exclusion from God's blessings and a further hardening (see commentary on 9:18) and darkening (as in Romans 1:21).
11:11-15 The stumbling of his own people from faith has resulted in a great harvest of faith among the other nations (15:16-19; Colossians 1:23). And Paul's hope is that Israel will eventually become jealous and again be included to enjoy God's blessings. He obviously looks forward to this as a future resurrection for the Jewish people. This is perhaps based on Ezekiel 36:26-27; 37:12- 14, where the work of the Spirit is the key to the renewal.
11:16-17 To make his point Paul uses the image of branches connected with a continuing olive tree of faith in God's power and fruitfulness. In the parable of the Vine the Holy Spirit corresponds to the sap in the individual believer's branch. In this parable of the Olive Tree the Holy Spirit corresponds to a nation's sharing in "the richness of the olive tree" (11:17 margin).
11:18-21 The new Gentile believers should not boast in their own strength. Their only status is by faith in God's power. And we remind ourselves that this kind of faith (Romans 4) gives us the power to live and act as did Old Testament believers. Abraham received power to move from Ur of the Chaldees, to procreate in his old age, and he believed in God's power to raise Isaac. Moses crossed the Red Sea, and others "won strength out of weakness" in all sorts of situations (Hebrews 11:8, 11, 17-19, 29, 34).
11:22 God is both kind to those who look to him, and very tough with those who try to live by their own strength.
11:23-27 Paul again thinks of the severed branches of his own people being grafted back into the life of the olive tree of faith (11:12, 15). He then shares his insight into the mystery of a future for the Jewish people. This may need to wait till the "full number" of other nations have come in.
11:28-32 The choice of the patriarchs (see patriarchs under 9:5) remains irrevocable. Just as the Gentiles moved from disobedience to faith and acceptance of God's mercy, so also the door is still open for Paul's own people.
11:33-36 Just writing about the incredible wisdom and power of God makes Paul realize he knows very little, except that all is from God, and through God, and for God's glory (see 9:4 under glory).