Hosea, Paul and the final conversion of Israel

Hosea and Gomer (Bible Historiale, 1372)

This is what we read in Hosea (8th-century BC prophet in Israel): 

₄ For the Israelites must live many days without a king or prince, without sacrifice or sacred fertility pillar, without ephod or idols. ₅ Afterward, the Israelites will turn and seek the Lord their God and their Davidic king. Then they will submit to the Lord in fear and receive his blessings in the future. (Hosea 3:4-5 NET)

And this is the relative comment by Father Augustine Lemann (1839 - 1909, a Jew converted to Catholicism in 1854):

“These carnal Israelites, who today refuse to believe in Jesus Christ, will one day believe in Him, that is, their descendants will do so, for Hosea foretells their conversion in the following terms: 'The children of Israel shall sit many days without king, and without prince, and without sacrifice, and without altar, and without ephod and without theraphim.' Who is there who does not see in this a portrait of the present state of the Jewish people? But listen to what the prophet adds : 'And after this the children of Israel shall return, and shall seek the Lord their God, and David their king: and they shall fear the Lord, and His goodness in the last days.' Nothing can be clearer than this prophecy, in which David evidently stands for Jesus Christ. Christ, says the Apostle, is born of the line of David according to the flesh.” (Father Augustine Lemann, Histoire Complète de l'Idée Messianique chez le peuple d'Israël, 1909 - pp. 443-445 [translation from the French by MdS])

Hosea certainly deals with the idolatry of his day, of which the repeated prostitution of Gomer, his wife, is a figure. But it is also a prophecy of Israel's future repentance, achieved only after the prolonged loss of independence, and only after they have renounced for good all forms of idolatry. But the expressions "without sacrifice", "without ephod" have no apparent connection with the repudiation of idolatry, and may suggest that the time framework is very ample, and includes the end of the priestly sacrifice, which definitively ended only in 70 CE.

When the Babylonian captivity finished with the fall of Babylon to the Persian king Cyrus the Great in 539 BCE, and the exiled Jews began to return to the land of Judah, they had already abandoned all idolatrous practices, and never resumed them. It was precisely from then on that their Messianic expectations started growing.

In Romans 9-11, Paul speaks extensively of the rejection by God of the Jewish people, which has not recognized the Messiah, Jesus Christ. At Rom 9:25-26 he quotes Hosea 2:23 and 1:10  Hosea 1:10, apparently interpreting Hosea's prophecy ("Although [lit. 'in the place'] it was said to them, “You are not my people,” it will be said to them, “You are children of the living God!”), with reference to God's new people, "not only from the Jews but also from the Gentiles" (Rom 9:24).

Did Paul really quote those verses from Hosea with reference not to the Israelites but to his new people formed by converted Jews and Gentiles alike?

There are several theories.

Some propose a "spiritualizing" approach, whereby Paul has reinterpreted the passage from Hosea, attributing it to the "new people" of God, formed by Jews and Gentiles. (see, for instance, George, Eldon Ladd, in The Meaning of the Millennium: Four View, p. 24).

Some affirm that Paul is applying the prophecy to Israel, according to the obvious sense of the text. (See, for instance, John A. Battle, "Paul's Use of the Old Testament in Romans, 9:25-26" in Grace Theological Journal, Vol. 2 No 1, Spring 1981, pp. 115-129: "this approach has the distinct asset of taking Hosea’s prophecy at face value and maintaining complete harmony between Hosea and Paul" p. 122)

A third approach is to consider to consider the conversion to the Messiahship of Jesus Christ  that has happened to a minority of Jews and mostly to Gentiles as a prophecy of the full restoration of Israel. As Scott J. Hafemann says, "Just as God can bring Israel back from the dead, he can also call Gentiles to new life."

See also here:

What Paul does here is to take this promise, which referred to a situation within the frontiers of the chosen people, and extract from it a principle of divine action which in his day was reproducing itself on a world-wide scale. In large measure through Paul’s own apostolic ministry, great numbers of Gentiles, who had never been “the people of God” and had no claim on his covenant mercy, were coming to be enrolled among his people and to be recipients of his mercy. (F.F. Bruce, TNTC Romans, 2015, IVP ebook, Rom 9:25-26)

This approach finds its corroboration in what Paul says in Romans 11, where he speaks of the "mystery" of the "partial hardening [has] has happened to Israel until the full number of the Gentiles has come in" (Rom 11:25). But in the end, also Israel will be fully converted: "For God has consigned all people to disobedience so that he may show mercy to them all." (Rom 11:32)