Romans 11:26-27 — And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob:
For this is my covenant unto them, when I shall take away their sins.
and so — what follows is related to what has been written so far.
all Israel — the nation as a nation, but not those who don't believe
the quote is from Isaiah 59:20-21 — And the Redeemer shall come to Zion, and unto them that turn from transgression in Jacob, saith the LORD. As for Me, this is My covenant with them, saith the LORD; My spirit that is upon thee, and My words which I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed's seed, saith the LORD, from henceforth and for ever. And Jeremiah 31:33 — But this shall be the covenant that I will make with the house of Israel; After those days, saith the LORD, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be My people.
shall be saved — at the start of Christ's Millennial reign
Deliverer (in Hebrew) = kinsman-redeemer-avenger
Hebrews 8:10-11 — For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put My laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to Me a people: And they shall not teach every man his neighbour, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest.