People will insist all includes jew and gentile as one unit. All the elect.
But of one reads romans 11. The who chapter is speaking about the difference between Jew and Gentile.
Nothing in romans 11 hints that Paul is speaking of any gentile when he claims all isreal will be saved.
Paul is quoting Isaiah 59:20.
Isa 59:20 And the Redeemer shall come to Zion, and unto them that turn from transgression in Jacob, saith the LORD.
Isa 59:21 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.
Dispensationalist apparently stop reading at Isa 59:21 but the story continues in chapter 60.
Isa 60:3 And the Gentiles shall come to thy light, and kings to the brightness of thy rising.
Isa 60:4 Lift up thine eyes round about, and see: all they gather themselves together, they come to thee: thy sons shall come from far, and thy daughters shall be nursed at thy side.
Isa 60:5
Then thou shalt see, and flow together, and thine heart shall fear, and be enlarged; because the abundance of the sea shall be converted unto thee, the forces of the Gentiles shall come unto thee.
So ALL TRUE ISRAEL, Jews and Gentiles shall be saved. And that's exactly what Paul is saying in Romans 11.
Rom 11:24
For if thou wert cut out of the olive tree which is wild by nature, and wert graffed contrary to nature into a good olive tree: how much more shall these, which be the natural branches, be graffed into their own olive tree?
Rom 11:25 For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.
Rom 11:26 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:
Two olive trees - one wild and one natural... So all olive trees shall be saved, both the natural branches and the grafted in branches. So ALL ISRAEL (wild and grafted in) shall be saved.