“Lest you be wise in your own conceits, I want you to understand this mystery, brethren: a hardening has come upon part of Israel, until the full number of the Gentiles come in, and so all Israel will be saved; as it is written, ‘The Deliverer will come from Zion, he will banish ungodliness from Jacob” Rom 11:25–26.
All Israel means the entire tribal family of Israel, a collective group representing all twelve tribes Rev 7:1–8, the new Israel, the assembly of Jews and Gentiles who form the Catholic Church together with an assembly of faithful Israelites from all twelve tribes across the ages of pre-Christian history. Lumen Gentium, Chapter II § 9, published by Pope Paul VI on November 21, 1964, says: “Israel according to the flesh, which wandered as an exile in the desert, was already called the Church of God. So likewise the new Israel which while living in this present age goes in search of a future and abiding city is called the Church of Christ.”
All Israel does not mean every individual Israelite.
After the Babylonian Exile and the “ten lost tribes,” most surviving Israelites traced their lineage to the tribe of Judah, with much smaller numbers to the tribes of Benjamin and Levi. Rabbi Paul calls them Jews Rom 1–8. In his time Jew was used more broadly to include anyone who followed Mosaic Judaism including Temple worship.
However, when Rabbi Paul reaches Rom 9–11 he switches to Israel. Israel traces its lineage back further, to the national family of twelve tribes descended from Jacob-Israel Gen 32:28: Reuben, Simeon, Levi, Judah, Issachar, Zebulun, Ephraim, Manasseh, Benjamin, Dan, Naphtali, Gad, and Asher Gen 35:23–25.
Rabbi Paul, who had studied under Rabbi Gamaliel I (the Elder) Acts 22:3, knew that David‘s kingdom unified all of the twelve tribes under the anointed king 2 Sam 5:1–5; 1 Kings 11:42. It reached beyond the borders of Israel to include the Gentiles 1 Kings 4:21; Ps 2:8; 72:8–11.
Rabbi Paul saw that Rabbi Yeshua, the Son of David, with his New and Eternal Covenant, quoting Isaiah in Rom 11:26–27, had fulfilled David‘s kingdom. Rabbi Yeshua selected twelve shlikhim to signify the messianic restoration of Israel Mt 10:2–5, sent them out to recover the “lost sheep” of Israel Mt 10:6, and promised to seat them on twelve thrones over the “twelve tribes of Israel” Mt 19:28. Today’s Catholic bishops are the successors of the shlikhim seated over the twelve tribes.
By contrast, Rabbi Paul saw the Mosaic Covenant as something that condemns rather than saves Acts 13:38; Rom 3:20; 2 Cor 3:4–11. There is no alternate way of salvation apart from Rabbi Yeshua‘s grace Rom 10:14–17; § 765; 839-840.
All Israel, in Hebrew kol israel, is the entire Jewish nation’s rabbinic acceptance of Rabbi Yeshua‘s national revelation, including all twelve tribes of the eternal election, those now called Jews, plus the ten tribes God raised up with a mighty hand into the Catholic Church as Ezekiel prophesied in his vision of the dry bones Ezek 37:4, 11–12; and Rabbi Yeshua fulfilled in Mt 27:51–53, all baptized into Rabbi Yeshua‘s Final Sacrifice Rom 6:3–4.
But if some of the branches were broken off, and you, a wild olive shoot, were grafted in their place to share the richness of the olive tree, do not boast over the branches. If you do boast, remember it is not you that support the root, but the root that supports you. You will say, “Branches were broken off so that I might be grafted in.” That is true. They were broken off because of their unbelief, but you stand fast only through faith. So do not become proud, but stand in awe. For if God did not spare the natural branches, neither will he spare you. Note then the kindness and the severity of God: severity toward those who have fallen, but God’s kindness to you, provided you continue in his kindness; otherwise you too will be cut off. And even the others, if they do not persist in their unbelief, will be grafted in, for God has the power to graft them in again. For if you have been cut from what is by nature a wild olive tree, and grafted, contrary to nature, into a cultivated olive tree, how much more will these natural branches be grafted back into their own olive tree. Rom 11:17–24.
We have seen the prophecy. God told Ezekiel,
“Son of man, these bones are the whole house of Israel. Behold, they say, ‘Our bones are dried up, and our hope is lost; we are clean cut off.’ Therefore prophesy, and say to them, Thus says the Lord GOD: Behold, I will open your graves, and raise you from your graves, O my people; and I will bring you home into the land of Israel” Ezek 37:11–12.
We have also seen the fulfillment.
“And behold, the curtain of the temple was torn in two, from top to bottom; and the earth shook, and the rocks were split; the tombs also were opened, and many bodies of the saints who had fallen asleep were raised, and coming out of the tombs after his resurrection they went into the holy city and appeared to many” Mt 27:51–53.
But the most central passage is:
§ 674 The glorious Messiah’s coming is suspended at every moment of history until his recognition by all Israel, for “a hardening has come upon part of Israel” in their unbelief toward Jesus. St. Peter says to the Jews of Jerusalem after Pentecost: “Repent therefore, and turn again, that your sins may be blotted out, that times of refreshing may come from the presence of the Lord, and that he may send the Christ appointed for you, Jesus, whom heaven must receive until the time for establishing all that God spoke by the mouth of his holy prophets from of old.” Acts 3:19–21. St. Paul echoes him: “For if their rejection means the reconciliation of the world, what will their acceptance mean but life from the dead?” Rom 11:15. The full inclusion of the Jews in the Messiah’s salvation, in the wake of the full number of the Gentiles, will enable the People of God to achieve the measure of the stature of the fullness of Christ, in which God may be all in all.
More on All Israel in The Catholic Church.