Ambrose of Milan — as excerpted in the Catena Aurea on Luke 1:5-7

“Divine Scripture teaches us with respect to those whom we commemorate, that not only the characters of the men themselves, but of their parents also, ought to be praised, that they might be distinguished by an inheritance, as it were, handed down to them of unspotted purity. Now not only from his parents, but also from his ancestors, St. John derives his illustrious descent, a descent not exalted by secular power, but venerable from its sanctity. Complete then is that praise which comprehends birth, character, office, actions, and judgments. The office was that of the Priesthood, as it is said, A certain Priest of the name of Zacharias.”