Gregory of Nazianzus
Catena Aurea · Lukasevangelium 1
And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. For with God nothing shall be impossible. And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word. And the angel departed from her.
(Carm. 18. de Geneal. Christi.) But some one will ask, How is Christ related to David, since Mary sprang from the blood of Aaron, the angel having declared Elisabeth to be her kinswoman? But this was brought about by the Divine counsel, to the end that the royal race might be united to the priestly stock; that Christ, Who is both King and Priest, might be descended from both according to the flesh. For it is written, that Aaron, the first High Priest according to the law, took from the tribe of Judah for his wife Elisabeth, the daughter of Aminadab. (Exod. 6:23.) And observe the most holy administration of the Spirit, in ordering that the wife of Zacharias should be called Elisabeth, so bringing us back to that Elisabeth whom Aaron married.