Luke 11:51

(Orat. in Diem Nat. Christi.) But some say that Zacharias, the father of John, by the spirit of prophecy forecasting the mystery of the immaculate virginity of the mother of God, in no wise separated her from the part of the temple set apart for virgins, wishing to show that it was in the power of the Creator of all things to manifest a new birth, while he did not deprive the mother of the glory of her virginity. Now this part was between the altar and the temple, in which was placed the brazen altar, where for this reason they slew him. It is said also, that when they heard the King of the world was about to come, from fear of subjection they designedly attacked him who bore witness to His coming, and slew the priest in the temple.

Why He begins from the blood of Abel, who was the first martyr, we need not wonder; but why, to the blood of Zacharias, is a question, since many were slain after him even up to our Lord's birth, and soon after His birth the Innocents, unless perhaps it was because Abel was a shepherd, Zacharias a Priest. And the one was killed in the field, the other in the court of the temple, martyrs of each class, that is, under their names are shadowed both laymen, and those engaged in the office of the altar.

But our Lord shows that the Jews have inherited the malice of Cain, since he adds, From the blood of Abel, to the blood of Zacharias, &c. Abel, inasmuch as he was slain by Cain; but Zacharias, whom they slew between the temple and the altar, some say was the Zacharias of old time, the son of Jehoiadah the Priest.

(Geometer.) But others give another reason for the destruction of Zacharias. For at the murder of the children the blessed John was to be slain with the rest of the same age, but Elisabeth, snatching up her son from the midst of the slaughter, sought the desert. And so when Herod's soldiers could not find Elisabeth and the child, they turn their wrath against Zacharias, killing him as he was ministering in the temple.