'Serving' in the Bible

And the firstborn of our sons and beasts--as it is written in the law--and the firstborn of our cattle and sheep, to bring to the house of our God [and] to the priests serving in the house of our God.

When Eliashib, Joiada, Johanan, and Jaddua were serving, the descendants of Levi were recorded as heads of their ancestors' houses, as were the priests during the reign of Darius the Persian.

On that same day men were placed in charge of the rooms that housed the supplies, contributions, firstfruits, and tenths. The legally required portions for the priests and Levites were gathered from the village fields, because Judah was grateful to the priests and Levites who were serving.