So where do we draw the line?
For starters...we are all the seed of Abraham IF we are in Christ.
This includes any who identify as Jewish today.
For ye are all the children of God by faith in Christ Jesus. For as many of you as have been baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus. And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise. Galatians 3:26-29
Challenge question: what is the genetic qualification to be a Jew today?
Where is the genetic line in the sand to be drawn exactly?
In America the qualifications for recognition in some of the native tribes ranges from 1/2 to 1/16 degree of Native American blood depending on the tribe. Even they do not expect 100%.
Anyone would be hard pressed today to find a 100% genetic descendant of Abraham today. I would say statistically this would be an impossibility and so far the genetic sciences agree as well as a lot of interracial relations have occurred since Abraham’s time.
No wonder Paul said to not get caught up in endless genealogies.
Neither give heed to fables and endless genealogies, which minister questions, rather than godly edifying which is in faith: so do. 1 Timothy 1:4
Jewish people need Jesus as much as any atheist, Muslim or any other non-believer.
To take the popular dispensational position of the day on the matter of Israel is heretically dangerous as it forms very wrong conclusions.
I am not being anti-Semitic here but only pointing out the Biblical fact that everyone needs Jesus in the same way. I really try to love everyone equally and just like God’s heart, I would rather none to perish but for all to come to repentance. (2 Peter 3:9)
There is only one way to heaven for all of mankind and that is through the spilt blood of Jesus Christ and this is without exception.
For all have sinned, and come short of the glory of God; Being justified freely by his grace through the redemption that is in Christ Jesus: Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God; To declare, I say, at this time his righteousness: that he might be just, and the justifier of him which believeth in Jesus. Where is boasting then? It is excluded. By what law? of works? Nay: but by the law of faith. Therefore we conclude that a man is justified by faith without the deeds of the law. Is he the God of the Jews only? is he not also of the Gentiles? Yes, of the Gentiles also: Seeing it is one God, which shall justify the circumcision by faith, and uncircumcision through faith. Romans 3:23-30
But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building; Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us. For if the blood of bulls and of goats, and the ashes of an heifer sprinkling the unclean, sanctifieth to the purifying of the flesh: How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God? And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance. For where a testament is, there must also of necessity be the death of the testator. For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth. Whereupon neither the first testament was dedicated without blood. For when Moses had spoken every precept to all the people according to the law, he took the blood of calves and of goats, with water, and scarlet wool, and hyssop, and sprinkled both the book, and all the people, Saying, This is the blood of the testament which God hath enjoined unto you. Moreover he sprinkled with blood both the tabernacle, and all the vessels of the ministry. And almost all things are by the law purged with blood; and without shedding of blood is no remission. It was therefore necessary that the patterns of things in the heavens should be purified with these; but the heavenly things themselves with better sacrifices than these. For Christ is not entered into the holy places made with hands, which are the figures of the true; but into heaven itself, now to appear in the presence of God for us: Nor yet that he should offer himself often, as the high priest entereth into the holy place every year with blood of others; For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself. And as it is appointed unto men once to die, but after this the judgment: So Christ was once offered to bear the sins of many; and unto them that look for him shall he appear the second time without sin unto salvation. Hebrews 9:11-28