Yes, but since you said God, then I assumed you were referring to the Israel He was going to restore, which He has done. You are pointing to the nation of Israel over the Israel of God which He was referring to in the restoration. The Kingdom was taken from Israel and given to the New Israel, His Israel made up from people of all nations.
The (part of) Israel that will be saved is not the (part of) Israel that is saved today.
Isaiah 41:8
But thou, Israel, art my servant, Jacob whom I have chosen, the seed of Abraham my friend.
Isaiah 41:17
When the poor and needy seek water, and there is none, and their tongue faileth for thirst, I the Lord will hear them, I the God of Israel will not forsake them.
Did you think Israel here was you?
It seems clear who God calls Israel
30 Thus shall they know that I the Lord their God am with them, and that they, even the house of Israel, are my people, saith the Lord God.
Do you think God is talking about the Raptured Bride when we this?
Joel 3:2
I will also gather all nations, and will bring them down into the valley of Jehoshaphat, and will plead with them
there for my people and for my heritage Israel, whom they have
scattered among the nations, and parted my
land
Can you remind us when Christians were 'scattered'?
If Israel were just believers what is this talking about?
Acts 9:15
But the Lord said unto him, Go thy way: for he is a chosen vessel unto me, to bear my name before the Gentiles, and kings, and the children of Israel:
Paul was to bear His name before Israel. You thought that meant he was Israel and was preaching to himself?
Who was he talking to here if there only Israel was Christians?
Acts 13:16
Then Paul stood up, and beckoning with his hand said,
Men of Israel, and ye that fear God, give audience.
So I think the truth is that not all Israel are the true children of God by faith, but they are still Israel! Once they do accept Jesus in the end and all Israel is saved, then they will all be the true Israel! The Jews who were and are saved before that, of course are already part of the true Israel. But you can't wave Israel away over a few verses in the New Testament taken out of context.
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.
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:
27 For this is my covenant unto them,
when I shall take away their sins.
The blindness of Israel (that keeps them from being 'true' Israel) will be TAKEN AWAY in the end! ALL Israel then will be saved.