John the Baptist refers says those coming to see him are the spawn of vipers, so when Jesus comes to see him whose spawn is he? (Luke 3:7) Is Jesus the spawn of vipers, since he comes to see John and is baptized by John? How is it possible that humans can be their spawn? What about when Jesus calls someone the sons of Cain and indicates this is the opposite of being a son of Abraham? We know that Cain's children die in the flood, yet Jesus calls some men the sons of Cain. (John 8:41) So did Cain's descendants not die? You see it is not about genetics at all.
. . . I agree that it's all about genetics. And you might be surprised to find that genetics prove Yeshua's messianic claims beyond any reasonable doubt.
I don't know how familiar you are with the theological dynamics/theories of the Flood, but many educated theologians claim that the design (purpose) of the Flood was to wipe out the nephilim (Cain's descendants) so that they wouldn't completely contaminate the pure line of Seth, coming through Noah (the nephilim infiltrate the line of Seth, Gen. 6).
It's actually the opposite. God doesn't cause the Flood to wipe out the nephilim. The attempt to wipe out the nephilim is itself an attempt to deny the birth of Christ. Christ line must come through the line of Cain and Seth or he has no right to his messianic claim.
If the nephilim got wiped out completely, i.e., if Cain's line was eliminated in the flood, then Yeshua cannot be Messiah.
But God slipped the principalities and powers a fast one. And it's writ large in the text of the scripture.
Naamah survived the flood as Noah's wife. And Naamah is nephilim (from the line of Cain). Noah's sons and daughters are of the line of Seth because Noah's genes purify the birth of his offspring (scripture says his line is pure, i.e., through Seth). . . So how does Cain's line continue after the flood if Noah's genes purify Naamah's genes through procreation?
Although Noah's sons are not nephilim, because of Noah's genes, a strange event happens in the text whose meaning is clear as day, but which the expositors ignore and gloss over. One of Noah's sons "uncovers Noah's nakedness." In the Tanakh, this is a euphemism for having sex with a man's wife.
In Jewish scripture we find that Noah starts getting drunk after the Flood because he was given a commandment to be fruitful and multiply, but finds himself unable to impregnate Naamah after the flood. Senescence has set in. Noah's son, seeing the depression setting into Noah, hatches a scheme. He and Naamah conspire to make Noah think he's fulfilling God's commandment by having a son such that Naamah and Ham have sex giving birth to Canaan.
Noah takes one look at Canaan coming out of the womb and knows exactly what has taken place. Although Noah's son's genes are pure, by reason of Noah's genes, they nevertheless have enough nephilim blood that when Ham's genes mix with Naamah, who is fully nephilim, Canaan comes out exhibiting the full traits of the nephilim. Noah knows what happened and is forced to curse Canaan right out of the womb since he knows his birth means Cain's lineage has survived the flood hidden in Naamah and Ham's genes.
Though in much theology Canaan's birth thwarts the purpose of the Flood, in God's design it befouls the attempt to destroy the birth of the true "firstborn of creation" who must come through the line of Cain as well as Seth.
John