Rom 9:1-5 – Paul laments the unbelief of Israel, notwithstanding her many spiritual blessings (cf. Rom 3:1-4).
Rom 9:6-13 – Israel’s unbelief does not frustrate the “word of God,” b/c “they are not all Israel, which are of Israel” (9:6); election is wrought not through “children of the flesh,” but through “children of the promise,” who are freely elected by God (9:8, 11).
Rom 9:14-18 – There’s no unrighteousness with God, b/c he distributes mercy and hardening on whom he will.
Rom 9:19-21 – God is sovereign over his creatures, just as a potter is sovereign over his clay.
Rom 9:22-33 – A thought-experiment, signalled as such as by the “ei de,” “what if,” that introduces it (this is an insight I recently learned from David Hart). Say that God has inscrutably prepared some (the Church) for glory, and others (unbelieving Israel, i.a.) for wrath; aren’t there plenty of passages in the prophets (Hosea and Isaiah, for instance) that suggest exactly this kind of reversal? (Notice that, by Rom 9:31 at least, “Israel” once again refers to the elect, and most hardened and unbelieving, descendants of Abraham, a meaning it appears to retain all the way through to Rom 11:26).
Rom 10:1-13 – Again, Paul longs for Israel’s salvation (10:1); the obstacle is that they have sought salvation, not in “the righteousness of the faith,” but rather in the “righteousness of the Law,” not knowing that Christ has brought the Law to its fulfillment (Rom 10:3-5). Confession of Jesus as Lord is what both Jew and Gentile need for salvation, and Israel has rejected this word (Rom 10:6-13).
Rom 10:14-21 – Again, the reversals of the Gospel. The good news has gone out into the world, but the LORD’s people has rejected it, and a people ignorant of the LORD has received it.
Rom 11:1-10: Has God abandoned Israel? No – he’s graciously preserved a faithful remnant even as the rest has been hardened.
Rom 11:11-24 – Was the whole point of now-hardened Israel being elected so that they would “fall”? (11:11) No – the introduction of Gentiles might, Paul hopes, provoke them jealously to return (11:11-14), because their proper place will always be in the elect people (11:15-17); they are always free to come back in (11:23), and indeed, the Gentiles who have come in always stand at risk of being cast back out for unbelief (11:21).
Rom 11:25-32 – Israel’s blindness will only endure “until the fulness of the Gentiles is brought in”; at that time, “all Israel will be saved,” b/c “the gifts and calling of God are irrevocable” (11:25-26) – God isn’t giving up on his people. The Gentiles “obtained mercy” through Israel’s “unbelief,” but Israel will obtain mercy through the mercy the Gentiles received (11:30). This has universalist consequences: “God hath concluded them all in unbelief, that he might have mercy upon all” (11:32, cf. 5:18).
Rom 11:33-36 – This is an extraordinary mystery; God be praised.
Summary thoughts: perhaps Paul’s meditation on the vessels of wrath and glory in Romans 9 is not meant to describe God’s actual purposes in election and reprobation, but to establish an a fortiori — even if God this is what God were up to, he wouldn’t be unjust. Perhaps, as seems to be the case in Romans 11, what God is actually up to in election and reprobation is working out the salvation of “all Israel” (11:26), to the end that he might “have mercy upon all” (Rom 11:32).