Answers for a Jew
Why do the Gospels contain two genealogies of Joseph? (beginning)
Question: If Jesus was not the son of Joseph by birth, why do the Gospels mention his genealogy? And why are Joseph's genealogies in the Gospels of Matthew and Luke different?
Answer: In his comments on the genealogy according to the Gospel of Matthew, Blessed Theophilact of Bulgaria writes: «Why does it give us the genealogy of Joseph, but not of the Blessed Virgin? What part did Joseph play in the Virgin Birth? Since Joseph was not Jesus' birth father, we cannot trace the genealogy of Jesus from Joseph. But listen: It is true that Joseph played no part in the birth of Jesus; therefore, it was necessary to give the genealogy of Virgin Mary. However, since the Law did not allow for a person's lineage to be traced through the mother [Num 36:6], Matthew did not mention the genealogy of the Holy Virgin. But after giving the genealogy of Joseph, he gives Mary's genealogy also, and for the following reason: the Law forbade taking a wife from a different tribe, clan, or family – only from your own tribe and clan. Since such was the prescription of the Law, in giving the genealogy of Joseph it was fitting to give also the genealogy of the Holy Virgin. For she was from the same tribe and clan as he was. For if it was not so, how could she have been engaged to him? So, the Gospel writer, in recording Mary's genealogy after Joseph's, obeyed the Law which forbade tracing one's lineage through the mother. He referred to him as the husband of Mary according to the common usage, for we have a tradition of calling a man engaged to be married as "husband" even before the actual marriage» (Commentary on the Gospel of Matthew, Mt 1:16).
(to be continued)