.

Reply Obj. 1: Faustus the Manichean argued thus, in the desire to
prove that Christ is not the Son of David, because He was not
conceived of Joseph, in whom Matthew's genealogy terminates.
Augustine answered this argument thus (Contra Faust. xxii): "Since
the same evangelist affirms that Joseph was Mary's husband and that
Christ's mother was a virgin, and that Christ was of the seed of
Abraham, what must we believe, but that Mary was not a stranger to
the family of David: and that it is not without reason that she was
called the wife of Joseph, by reason of the close alliance of their
hearts, although not mingled in the flesh; and that the genealogy is
traced down to Joseph rather than to her by reason of the dignity of
the husband? So therefore we believe that Mary was also of the family
of David: because we believe the Scriptures, which assert both that
Christ was of the seed of David according to the flesh, and that Mary
was His Mother, not by sexual intercourse but retaining her
virginity." For as Jerome says on Matt. 1:18: "Joseph and Mary were
of the same tribe: wherefore he was bound by law to marry her as she
was his kinswoman. Hence it was that they were enrolled together at
Bethlehem, as being descended from the same stock."

Reply Obj. 2: Gregory of Nazianzum answers this objection by saying
that it happened by God's will, that the royal family was united to
the priestly race, so that Christ, who is both king and priest,
should be born of both according to the flesh. Wherefore Aaron, who
was the first priest according to the Law, married a wife of the
tribe of Juda, Elizabeth, daughter of Aminadab. It is therefore
possible that Elizabeth's father married a wife of the family of
David, through whom the Blessed Virgin Mary, who was of the family of
David, would be a cousin of Elizabeth. Or conversely, and with
greater likelihood, that the Blessed Mary's father, who was of the
family of David, married a wife of the family of Aaron.

Again, it may be said with Augustine (Contra Faust. xxii) that if
Joachim, Mary's father, was of the family of Aaron (as the heretic
Faustus pretended to prove from certain apocryphal writings), then we
must believe that Joachim's mother, or else his wife, was of the
family of David, so long as we say that Mary was in some way
descended from David.

Reply Obj. 3: As Ambrose says on Luke 3:25, this prophetical passage
does not deny that a posterity will be born of the seed of