Saying he was the firstborn of Mary, would not have had the same significance because the Jewish custom did not recognize the mother's place but only the father's. That is not true. The patrilinear primogeniture had to do with inheritance. The first-born of the father was entitled to twice the inheritance of the other siblings.
Jewish Encyclopedia writes:
The primogeniture of inheritance refers to the first-born son on the side of the father by any of his wives (if he lived in polygamy).
Matrilinear pirmogeniture is different. As per Jewish Encyclopedia (my emphasis):
This law applies to the first-born of the mother and not of the father. Hence the husband of several wives would have to redeem the first-born of each one of them
The primogeniture of the mother refers to redemption, not inheritance. The JE explains:
The primogeniture of redemption refers to the male first-born on the mother's side and applies to both man and beast: "Sanctify unto me all the first-born, whatsoever openeth the womb among the children of Israel, both of man and beast: it is mine"(Ex. xiii. 2).
Hence Jesus was the firstborn of redemption, and he belonged to God, by Law (remember Gal 4:4 "born of a woman, born under the Law"?).
You people should not be interpreting anything form the Bible without thoroughly familiarizing yourselves with the customs, laws and the language of the times.
You people should not be interpreting anything form the Bible without thoroughly familiarizing yourselves with the customs, laws and the language of the times.This coming from that great Christian apologist, kosta50. "You people"?? A crowd of one surges forward with agnostic advice on Christian understanding. Much like installing stained glass windows in a mud hut.