I have taught Romans 9 many times to adults and will spend hours on it. You have to keep it in context of not only Ro. 9-11, but also all of Romans and what Paul is teaching. We like to pull verses out to support a point, but do not address why that verse was written to that place at that time.
Vessels of mercy did not have to be specifically “named” when God decided to glorify them and shower them with gifts.
You really need to put every verse in Ro. 9 in the context of at least all of Ro. 9, ro. 9-11 and all of Romans.
Romans 9
Paul uses two teaching methods throughout Romans even secular philosophy classes will use Romans as the best example of these methods. Paul does an excellent job of building one premise on the previous premises to develop his final conclusions. Paul uses an ancient form of rhetoric known as diatribe (imaginary debate) asking questions and most of the time giving a strong “By no means” and then goes on to explain “why not”. Paul’s method goes beyond just a general diatribe and follows closely to the diatribes used in the individual laments in the Psalms and throughout the Old Testament, which the Jewish Christians would have known extensively. These “questions or comments” are given by an “imaginary” student making it more a dialog with the readers (students) and not just a “sermon”.
The main topic repeated extensively in Romans is the division in the Christian house churches in Rome between the Jews and Gentile Christians. You can just look up how many times Jews and gentiles are referred to see this as a huge issue.
The main question (a diatribe question) in Romans 9 Paul addresses is God being fair or just Rms. 9: 14 What then shall we say? Is God unjust? Not at all!
This will take some explaining, since just prior in Romans 9, Paul went over some history of God’s dealings with the Israelites that sounds very “unjust” like “loving Jacob and hating Esau” before they were born, but remember in all of Paul’s diatribes he begins before, just after or before and just after with strong support for the wrong answer (this makes it more of a debate and giving the opposition the first shot as done in all diatribes).
Some “Christians” do not seem to understand how Paul, uses diatribes and think, since he just showed God being “unjust” and saying God is “not unjust” that God has a special God definition of “just”, making God “just” by His standard and appearing totally unjust by human standards. God is not a hypocrite and does not redefine what He told us to be true.
Who in Rome would be having a “problem” with God choosing to work with Isaac and Jacob instead of Ishmael and Esau? Would the Jewish Christian have a problem with this or would it be the Gentile Christians?
Think further about this: The Jews (thinking the gentiles were dogs) would support their distant for the Gentiles by pointing out to them how God: loved Jacob, a Jew, and hated Esau, a gentile, plus Jacob and Ishmael, Moses and Pharoah and with other OT true stories. Those true stories would thus be formular to both Jewish and Gentile Christians, showing the Jews were special and the ZGentiles were just common.
If God treaded you as privileged and special would you have a problem or would you have a problem if you were treated seemingly as common, while others were treated with honor for no apparent reason?
This is the issue and Paul will explain over the rest of Romans 9-11.
Paul is specific with the issue Rms. 9: 19 One of you will say to me: “Then why does God still blame us? For who is able to resist his will?”
The Jews were created in a special honorable position that would bring forth the Messiah and everyone else was common in comparison (the Gentiles).
How do we know Paul is specifically addressing the Jew/Gentile issue? Rms. 9: 30 What then shall we say? That the Gentiles, who did not pursue righteousness, have obtained it, a righteousness that is by faith; 31 but the people of Israel, who pursued the law as the way of righteousness, have not attained their goal. 32 Why not? Because they pursued it not by faith but as if it were by works. They stumbled over the stumbling stone.
Paul is showing from the position of being made “common” vessels by God the Gentiles had an advantage over the Israelites (vessels of honor) that had the Law, since the Law became a stumbling stone to them. They both needed faith to rely on God’s Love to forgive them.
Without going into the details of Romans 9-11 we conclude with this diatribe question: Romans 11: 11 Again I ask: Did they stumble so as to fall beyond recovery? Not at all! Rather, because of their transgression, salvation has come to the Gentiles to make Israel envious. 12 But if their transgression means riches for the world, and their loss means riches for the Gentiles, how much greater riches will their full inclusion bring!
The common vessels (gentiles) and the vessels of honor (Jews) are equal individually in what is really significant when it comes to salvation, so God is not being unjust or unfair with either group.
If there is still a question about who is being addressed in this section of Rms. 9-11, Paul tells us: Rms. 11: 13 I am talking to you Gentiles. Inasmuch as I am the apostle to the Gentiles, I take pride in my ministry 14 in the hope that I may somehow arouse my own people to envy and save some of them.
Rm 9:22 What if God, although choosing to show his wrath and make his power known, bore with great patience the objects of his wrath—prepared for destruction?
This verse is not saying all the “vessels” created for a “common purpose” were created for destruction (they were not made from the start by the Potter “clay pigeons”). Everything that leaves the potter’s shop is of great quality. Those vessels for destruction can come from either the common group or the honor group, but God is being patient with them that will eventually be destroyed. The vessels God does develop great wrath against, will be readied for destruction, but how did they become worthy of destruction, since they left the potter’s shop with his mark on them? Any vessel (honorable or common) that becomes damaged is not worthy of the potters signature and He would want it destroyed.
To understand this as Common vessels and special vessels look at the same idea using the same Greek words of Paul in 2 Tim 2: 20. There Paul even points out the common can become the honored vessel.
Just because Paul uses a Potter as being God in his analogy and Jerimiah 18 uses a Potter as being God in his analogy, does not mean the analogies are conveying the exact same analogy. Jerimiah is talking about clay on the potter’s wheel being change while still being malleable clay (which fits the changing of Israel), but Paul is talking about two finished pots (vessels) so they cannot both be Israel, the clay is the same for both and the clay is not changing the outcome of the pot. The two pots (vessels) are completed and a person is asking “Why did you make me like this”, so it is about “how a person is made (born)” and not a nation.
Since Jerimiah talks only about one pot on the wheel changing and Paul is talking about two kinds of completed pots (vessels), who are the two different pots?
Paul is saying in 2 Tim 2: 21 even after leaving the shop the common vessels can cleanse themselves and thus become instruments for a special purpose. So, who is the common vessel and who is the special vessel in this analogy?
That is a short explanation, since you really need to study all of Romans especially chapters 9, 10 and 11. Also please look at individual laments in the Psalms and diatribes in general, I really cut those short.