Question:
How is Christ called the Son of David, and as was supposed the Son of Joseph, and was the Son of neither after the flesh? How, then, can He be the Son of Man?
Answer:
He was not the Son of David through Joseph, only in law. He was the Son of David, in fact, and the Son of Man, in fact, by being born of Mary. “But when the fulness of the time was come, God sent forth his Son, made [born] of a woman…” (Galatians 4:4). The genealogy is reckoned, according to Jewish custom, through the father. Mary and Joseph sprang from David; when the two branches united in marriage, the son, not the daughter, was counted.