John Calvin Commentary Luke 1:9

"according to the custom of the priest`s office, his lot was to enter into the temple of the Lord and burn incense." — Luke 1:9 (ASV)

According to the custom of the priest’s office. The law commanded that incense should be offered twice every day, that is, every morning and in the evening (Exodus 30:7–8). The order of courses among the priests had been appointed by David, as we have already explained; and, consequently, what is stated here about incense was expressly commanded by the law of God. The other matters had been arranged by David (1 Chronicles 24:3), so that each family might have its own turn, though David ordained nothing that was not prescribed by the law: he only pointed out a plan by which they might individually perform the service that God had commanded.

The word temple (νὰος) is here used for the holy place; which deserves attention, as it sometimes includes the outer court. Now, Zacharias is spoken of as going into the temple, which only priests were permitted to enter. And so, Luke says that the people stood without, as there was a great distance between them and the altar of incense, for the altar on which the sacrifices were offered stood between.

It should also be noted that Luke says before God: for whenever the priest entered into the holy place, he went, as it were, into the presence of God, so that he might be a mediator between Him and the people. For it was the Lord's will to impress this upon His people: that no mortal is allowed access to heaven without a priest going before. Indeed, as long as people live on the earth, they do not approach the heavenly throne to find favor there, except in the person of the Mediator.

Now, although there were many priests, no two of them were permitted to perform the solemn office of intercession for the people at the same time; but they were arranged in classes so that only one entered the Holy Place, and thus there was only one priest at a time. The purpose of the incense was to remind believers that the sweet fragrance of their prayers does not ascend to heaven except through the sacrifice of the Mediator; and how these figures apply to us must be learned from the Epistle to the Hebrews.