There are several passages of scripture that confirm God's plan for His chosen nation Israel (Zech. 12:10, Rom. 11:26, Jer. 23:6, Isa. 45:17). What does it mean when Paul, writing under the inspiration of the Holy Spirit, reveals that all of Israel shall be saved? (Romans 11:25-27). In this verse Paul is referring to Isaiah 59:20, which is the promise that someday God will send the redeemer (Messiah) to Israel.
The Bible, both in the Old Testament and New Testament, teach us about the source of salvation. There is only one source of salvation, God Himself. Simply put, people (including Israel) are saved because of their faith in God that He will keep His Promises.
Please check out this link for more on understanding God's Promises Through Israel.
The "all" of Israel includes everyone who believed that someday God would fulfill all His promises and revelations including the promise to send this redeemer spoken about in Isaiah 59:20.
Those who believe in this redeemer are sometimes referred to as a remnant. Messianic Judaism recognizes that the disciples of Jesus were Jewish and that since then, there has always been a remnant of believing Jews in Jesus as the Messiah. Isaiah cries out concerning Israel: Though the number of the Israelites be like the sand by the sea, only the remnant will be saved (Isaiah 10:22, Romans 9:27).
Before that redeemer came, it was common to look forward to the day when He would come. While He was here, many Jews accepted Him (Jesus) as their redeemer (Messiah) although the San Hedrin Court did not officially recognize Jesus with this title. Since His death and resurrection, people look back to what was accomplished on the cross by Him being a substitute for our sin offering. For Jews who don't believe in Jesus now, most still look forward to His coming. Many (including ultra orthodox) include as part of their daily prayers what's referred to as Maimonides 13 Articles Of Faith, with article 12 stating, "I firmly believe in the coming of the Messiah; and although He may tarry, I daily hope for His coming."(1) Christians are looking foreword to the second coming of King Messiah while Jews are looking forward to what they believe will be His first coming. It is actually the exact same event.
End Time prophecy teaches that The Second Coming Of King Messiah will occur. When He comes, He will fight the end of Israel's final battle for them. The Nation of Israel (at the end of the Tribulation Period and Jacob's Trouble), will be given an understanding of this truth, the truth about Jesus being Israels' true Messiah, Redeemer and King. Israel will then experience what is written about by the prophet Zechariah, And I will pour out on the house of David and the inhabitants of Jerusalem a spirit of grace and supplication. They will look on me, the one they have pierced, and they will mourn for him as one mourns for an only child, and grieve bitterly for him as one grieves for a firstborn son (Zechariah 12:10).
This spirit of Grace and supplication will allow the remaining remnant of Israel to understand that Jesus was indeed their long awaited King and Messiah. With this faith in their hearts, "All" of the remaining nation (the remnant) of Israel alive at that time, will be saved. Learn more about the Zech. 12:10 Prophecy.
Right now this understanding is available on an individual level, but at the time of Messiah's second return it will be imputed to Israel on a national level (Possibly with an official declaration by the recently reconvened San Hedrin Court).
This is how one respected Biblical commentator puts it:
When the armies of the world surround Jerusalem (Zech 14:1-3), the High Priest and members of the Sanhedrin will realize, somehow, that Yeshua (Jesus) is their only hope. In desperation, they will fall on their faces and cry out, "Baruch Haba Bashem Adonai" ("Blessed is He who comes in the Name of the Lord") (Psalm 118:26). After the Sanhedrin is able to "see" Him with their spiritual eyes and make their messianic declaration (Psalm 118:26); then they will see Him with their physical eyes when He descends from the heavens to intervene in the Armageddon campaign (Rev. 16:16, 19:11-16).(2)
This is when Israel receives the new heart spoken about in Ezekiel. Moreover, I will give you a new heart and put a new spirit within you; and I will remove the heart of stone from your flesh and give you a heart of flesh. I will put My Spirit within you and cause you to walk in My statutes, and you will be careful to observe My ordinances (Ezekiel 36:26-27).
Isaiah teaches that For though your people, O Israel, may be like the sand of the sea, Only a remnant within them will return; A destruction is determined, overflowing with righteousness (Isaiah 10:22). The New Testament re-confirms the idea of only the remnant being saved when it teaches Though the number of the Israelites be like the sand by the sea, only the remnant will be saved (Romans 9:27).
But Israel will be saved by the LORD with an everlasting salvation... (Isaiah 45:17).
This is an in depth theological area of the Bible and this page is meant to encourage others to proceed with an independent study of this topic using this information along with prayer. Please pray for knowledge and understanding concerning God's word and His will and His ways. Also pray for wisdom and discernment concerning how to apply these things in your own individual life along with sharing this information with others. This page is a starting point.
No one has taken Israel's place. The gifts and calling of God are irrevocable (Romans 11:29).
In his days Judah will be saved and Israel will live in safety. This is the name by which he will be called: The LORD Our Righteousness (Jer. 23:6). Learn how the End Of The Law brings righteousness.
Jeremiah reveals more about Messiah's return (the Davidic Kingdom) in Jeremiah 33:14-21.
There is a connection between Joel 2:32 and all Israel will be saved.
At this time All of Israel will also be saved from having to be under control of foreign rulers since Jesus the Messiah was born a Jew and will rule His Kingdom from Jerusalem.
The Bible teaching "All Israel will be saved" (Romans 11:25-27) and the teachings of the Talmud that All Israel will have a share in the world to come (Talmud-Mas. Sanhedrin 90) are not connected. The Bible relates to the Nation of Israel at the time of the coming of Messiah while the Talmud relates to all Jews whoever lived.
1). The Complete ArtScroll Siddur p.178-179.
2). Christian Jew Foundation, Messianic Perspectives, May/June 2007