Regardless of Abraham's children. What?
Ethnic Israel as far as seeds (many) has nothing to do with the spiritual seed (one) Christ .
John 3:6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
God works the same way in all dispensations, by work of His faith as a labor of His love., purifying the hearts of men according to His perfect law. He puts no difference between a Jew and Gentile, never did never will .He simply is not a respecter of the color of one’s skin.
And God, which knoweth the hearts, bare them witness, giving them the Holy Ghost, even as he did unto us;And put no difference between us and them, purifying their hearts by faith. Act 15:8
Looking for a living hope in the flesh of Abraham as if it was the spiritual seed of Christ by which all men are born again was the downfall of the outward Jews .(no Spirit of Christ)
Not all Israel is born again Israel. Seeing if any man has not the Spirit of Christ then neither is he known by Christ.
Because His promise are two fold the temporal as that seen (flesh) an that not seen , the eternal.( Spirit)
2Corinthians 4:18 While we look not at the things which are seen, but at the things which are not seen: for the things which are seen are temporal; but the things which are not seen are eternal.
A distinction must be made between the seeds of Abraham (many) according to his flesh and the spiritual seed of Christ according to the spirit of Christ.
Galatians 3:16 Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.