'Serving' in the Bible

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.

Also at that time men were appointed over the storerooms for the contributions, for the first fruits, and for the tithes, so those portions required by the Law could be gathered from the fields adjacent to the towns to benefit the priests and descendants of Levi, for the people of Judah rejoiced over the priests and the descendants of Levi who were serving.