Paul is not teaching determinism; he is countering the deterministic views of his opponents
Background on the Epistle to the Romans
Paul is writing the Epistle to the Romans circa AD 56-57, prior to having ever preached personally in Rome. He is introducing himself & his message (and probably correcting misrepresentations of his message that have already spread to Rome). Paul has been appointed the "apostle to the Gentiles" (e.g. see Romans 11:13), and in this epistle he is addressing 2 major points of controversy (and plenty of minor ones) between Jewish Christians & Gentile Christians:
- Correcting the belief that justification comes through the Law of Moses (see esp. chapters 3-61)
- Clearly explaining that God's covenants are available to everyone, not just the Jews (see esp. chapters 9-11; this central thesis is also introduced right at the beginning of the letter, in Romans 1:16)
Setting up the Steel Man
Among at least a portion of the Jewish Christians in Rome there was a belief that they, as the physical descendants of Abraham, were uniquely ordained by God to receive the blessings of His covenants, whereas everyone else was ineligible. This deterministic (or at least quasi-deterministic) view essentially held that the circumstances of one's birth indicated whether they were "determined" to be received or rejected (e.g. see Rom. 9:3-5).
In the massive chiasmus occupying Romans 9-11 Paul builds up the principles of foreordination (we could also use the word "predestination" here, but I'll stick with "foreordination" as it is a less loaded term) that are essential to his opponents' argument, and then beats them at their own game by showing that their conclusions do not follow from their own premises.
The heart of the chiasmus
The center of the Romans 9-11 chiasmus is in chapter 10:
12 For there is no difference between the Jew and the Greek: for the
same Lord over all is rich unto all that call upon him.
13 For whosoever shall call upon the name of the Lord shall be saved.
Note that the emphasis in verse 13 is on the whosoever, not the call. The point is not to outline a checklist entitled "steps to salvation", but to clearly establish that God's covenant of grace--which Paul has spent much of this epistle outlining--is available to everyone. All people2. Jew & Greek. The entirety of humanity. Todos. Everybody.
Paul is already exposing chinks in his opponents' armor in chapter 9, but he'll complete his argument in chapter 11.
After acknowledging the unique role Israel plays in God's work, Paul points out that "Israel" is more than physical genealogy:
6 Not as though the word of God hath taken none effect. For they are
not all Israel, which are of Israel [spiritual Israel != physical
7 Neither, because they are the seed of Abraham, are they all
children: but, In Isaac shall thy seed be called. [Paul's point is nothing
new, he notes that his audience in fact already believes this: even the Israelites believed it was Isaac's line, not Ishmael's,
that inherited the promises made to Abraham...so being a physical
descendant of Abraham was not, even on their view, deterministic]
8 That is, They which are the children of the flesh, these are not
the children of God: but the children of the promise are counted for
the seed. [it's the children of the promise, not the children of the
body, who receive these blessings] (Romans 9:6-8, bracketed comments mine)
Children of the promise--what promises?
Paul has just covered this in the previous chapter:
14 For as many as are led by the Spirit of God, they are the sons of
15 For ye have not received the spirit of bondage again to fear; but
ye have received the Spirit of adoption, whereby we cry, Abba, Father.
16 The Spirit itself beareth witness with our spirit, that we are the
children of God:
17 And if children, then heirs; heirs of God, and joint-heirs with
Christ; if so be that we suffer with him, that we may be also
glorified together. (Romans 8:14-17)
The children of the promises--those who will inherit the blessings of Abraham--are not exclusively those who physically descended from Abraham (or Isaac)--but they are all those who are willing to be led by the Spirit of God. Regardless of their physical ancestry, they are adopted in, and are eligible to be full heirs of God's covenants.
Taking down the Steel Man
After establishing the universal nature of the Gospel of Jesus Christ at the heart of the chiasmus in chapter 10, Paul works his way back through the chiastic structure and corrects his opponents' misapprehension of foreordination in chapter 11. Let's compare the arguments on either side of the chiasmus.
From Romans 9:
I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion (v 15)
This is a quotation from Exodus 33:19, where God is granting graciousness & mercy to one who has sought Him "found grace in His sight"; a privilege not equally granted to those who were just described as stiff-necked and had spent the previous chapter laboring upon a golden calf. God chose to whom He would extend these blessings, but the decision was not arbitrary.
From Romans 11:
But what saith the answer of God unto him? I have reserved to myself seven thousand men, who have not bowed the knee to the image of Baal.
God didn't choose these people simply because of who their parents were--He chose those who were faithful to Him. Those who worshipped other gods--even Israelites who did so--did not deterministically receive the inheritance.
From Romans 9:
So then it depends not on human will or exertion, but on God, who has mercy (v 16)
You can't earn it. Moses & Jacob (both of whom Paul has just mentioned) didn't earn God's mercy. But God, who knows people from the beginning (see Jer. 1:5) and knows the heart (see 1 Sam. 16:7), gave them what they could never earn, and in so doing created a covenant with them.
Paul spent the last few chapters explaining that salvation came through Christ, not through strict, unwavering obedience to the Law of Moses. Paul teaches that God's people are not under the Law of Moses; they are under grace.
Grace, in Paul's world, did not mean a handout. Grace was a gift that was given through covenant or treaty: there were expectations of the recipient (see further discussion in my videos here & here). Moses & Jacob were recipients of God's covenants. God's covenants were extended to ancient Israel (though not all chose to accept/keep these covenants). Paul's glorious message is that even though you too cannot earn it, you cannot attain it through human will & exertion, God extends His covenants to you as well!. A portion of Paul's audience thinks they are better than their peers--he's telling them they are not.
Paul illustrates this reality in chapter 11, through the allegory of the olive tree (natural branches = physical Israel, wild branches = those adopted in). Those of physical Israel who are unbelieving are cut off from the olive tree, and no longer receive the "richness" of its roots (see vss. 17,20). Those who, though not of physical Israel, endure/persist/continue (ἐπιμένῃς, v22) and stand by faith (v20) are grafted into the tree and receive the richness of its roots.
Paul quickly warns, however, that those who were grafted in can still be cut off if they are prideful (v20), and those who have been cut off can still be rescued and returned to the tree if they turn from their unbelief (v23).
This is a decidedly non-deterministic theology. Paul does not dispute the Israelite claim to have been foreordained by God to be born into Israel--but he shows them, from their own prophets, history, and parables--that being born into Israel is not enough. One can gain access to God's covenants through faithfulness, and one can lose access through unfaithfulness. Although the Israelites received these opportunities first, they did not receive them exclusively: everyone, regardless of their family "tree" of origin, can be grafted in to be full heirs.
Hardening, Pottery, and Vessels of Wrath
he hardens whomever he wills (Romans 9:18)
This could more clearly be rendered "he leaves to their stubbornness" (see v18 footnote b here) or "he leaves them to pursue their own course" (see Barnes' commentary).
"Why does he still find fault? For who can resist his will?” 20 But who are you, O man, to answer back to God? Will what is molded say to its molder, “Why have you made me like this?” 21 Has the potter no right over the clay, to make out of the same lump one vessel for honorable use and another for dishonorable use? (Romans 9:19-21)
Recall that Paul is addressing an opposing argument. Here he raises the questions/objections his opponents would be likely to present, so that he may respond to them. Paul simply points out the arrogance of trying to tell God what He should or should not do. Flawed mortals with imperfect information may look at God's blessings to some & punishment of others and claim He is unjust. We have no grounds to make such an accusation.
Paul will continue to describe what God favors and disfavors as he develops his argument; here he addresses his opponents by asking them "who are you to tell God He's wrong to do something?" In the next few verses, Paul will elaborate on the clay analogy. In chapter 11, he will pair it with the allegory of the olive tree to explain why God blesses & chastises.
What if God, desiring to show his wrath and to make known his power, has endured with much patience vessels of wrath prepared for destruction (Romans 9:22)
This poor, tortured verse...it too has had to endure with much patience. The critical verb here, κατηρτισμένα (having been completely fitted, prepared), is not in active voice. God, the subject of the sentence, is not doing the action. Here Paul explains the clay analogy from the prior verse: God gives life to & sustains His creations--even the wicked ones--and permits them to pursue their chosen course3.
The unfaithful prepare themselves for destruction. By not immediately squashing the clay and starting over, God is in fact merciful: He endures, He puts up with them, He grants them a time and a space to repent. It is when they are completely fitted/prepared for destruction--by their own agency--that God metes out destruction. This too is demonstrated on the opposite side of the chiasmus--even the branches that have been cut off can be restored if they turn from their unfaithfulness. God will show His power, mete out justice, and use it as a teaching moment for future generations, but He reserves destruction until people are "fully ripe" in iniquity.
Paul demonstrates that we cannot earn God's grace or His mercy, but rejects the determinism percolating through some circles in Rome. While the circumstances of one's birth and the position they will occupy in life may well be pre-determined (Paul tacitly acknowledges the possibility but does not provide the criteria by which such a determination was made), the circumstances of one's birth do not determine whether one can be an heir to the promises Paul outlined in chapter 8.
When Paul's argument is considered in its entirety, rather than severed into isolated pieces, it is clear that Paul is responding to determinism, not teaching it. Those who are willing to be led by the Spirit and remain faithful may receive all of the promises of Abraham, regardless of their physical lineage.
1 These themes are weaved throughout the epistle, but these chapters in particular focus heavily on this matter.
2 The massive plot hole in so many theological discussions "what about the unreached", of course, remains unresolved by this statement. Paul isn't addressing the topic here, though arguably he does do so elsewhere in his writings. For a response to the problem of the "unreached", see my thoughts here & here.
3 Why God develops creations that He knows will choose to be dishonorable is a related but separate question. Naturally, it is also a matter of much theological debate.