And in this way all Israel will be saved, as it is written, “The Deliverer will come from Zion, he will banish ungodliness from Jacob”;  “and this will be my covenant with them when I take away their sins.” (ESV)
The Apostle Paul is referring in these verses to a prophecy by the prophet Isaiah. It speaks of the fact that there are those who belong to the nation of Israel who are going to be saved at a later time. They are the Elect of God, just as we understand that people of all races and peoples have been called by God to be his Elect.
One thing we have to be very careful about when we look at this passage of Scripture is to not misunderstand the nature of salvation. There is no salvation for anyone who does not repent of their sins and accept the sacrifice of the Savior's blood on their behalf. The Jews do not get a free pass here. Nor does anyone else. Not now. Not ever.
Those who are truly the Elect of God will receive God's gift of faith. They will be saved by His grace. They will acknowledge their sin and repent of it. One way we could look at what Paul says in verse 26 is, "All TRUE Israel will be saved." The true people of God are not the unbelieving, the mockers, the rebels, the reprobates, the idolaters.
The Deliverer in this passage of Scripture is obviously Jesus Christ himself. Some interpret this verse as being in a Millenial reign of Jesus Christ. I am not one of those people. I look to this deliverance as being in the "Church age" from the time of Christ's ascension until the time of Christ's return. Regardless of your eschatological view it is wonderful to know the salvation God has for his Elect.
God keeps his promises. His covenant relationship with his people is of great importance to the Savior. Let us praise God for the Jews who come to faith in Jesus Christ.