Can you prove that by reference to the Torah or a religious text?
Sure. I’ll be back.
Babylonian Talmud, Kidushin 68B, “Rabbi Yochanan said in the name of Rabbi Shimon Bar Yochai, scripture states, Deuteronomy 7, verse 3, et seq.: ‘you shall not marry them (the nations) and you shall not give youor daughter to his son nor take his daughter for your son, for he will cause your son to err from following Me, and they will serve other gods...’ your son from an Israelite is called ‘your son,’ but your son from a gentile is not called ‘your son’.”
Babylonian Talmud, Sanhedrin 43B, “Even if he has sinned, he is still an Israelite.”