This verb means to function as a priest, performing the ritual and sacrificial duties of the priesthood. In Jewish context, it involved offering sacrifices, burning incense, blessing the people, and maintaining temple worship. Luke 1:8 uses it to describe Zacharias performing his priestly service when he received the vision of Gabriel. The participle ἱερατεύειν indicates active engagement in priestly ministry during his division's week of temple service. Classical Greek used it for serving as priest of various deities. Translations render it as "serving as priest" or "exercising the priestly office," emphasizing the official cultic function.