Theophylact of Ohrid

Note also that Zacharias did not go to his house until the days of his service were completed, but remained in the temple. For the hill country was indeed far from Jerusalem. And a priest, even if he had a house in Jerusalem itself, was not permitted to leave the temple court during the time of his rotation. But we, alas, how we neglect the divine services! That Zacharias could not speak but used signs points to the senseless life of the Jews. …

Commentary on Luke ↗

Bede

During the time of their course, the priests of the temple were so occupied by their office, that they kept themselves not only from the society of their wives, but even from the very threshold of their houses. Hence it is said, And it came to pass, that, as soon as the days were accomplished, &c. For as there was then required a priestly succession from the root of Aaron, of necessity then a time was appointed for keeping up the inheritance. …

Catena Aurea by Aquinas ↗

Bonaventure

Therefore first mutual cohabitation is indicated, when he says: And it came to pass, when the days of his office were fulfilled, he went to his house, namely to cohabit and to render the debt to his wife; whence Chrysostom says that on the same night he begot a son. …

Commentary on Luke, Chapter 1 ↗