'Duty' in the Bible

And it was the primary [duty] of the trumpeters and singers to make themselves heard [with] one voice, to praise and give thanks to Yahweh. And when a sound from the trumpets, cymbals, and other instruments of song was raised to Yahweh--for he [is] good, because his loyal love [is] everlasting--then the house, the house of Yahweh, was filled with a cloud.

and the food of his table, and the position of his officers, the duty of his servants and their clothing, his cupbearers and their clothing, and his burnt offerings that he offered at the house of Yahweh, there was no longer any breath in her.

This is the thing that you must do: one third of you priests and Levites {coming off duty on the Sabbath} [shall be] gatekeepers at the entrances

And the Levites and all Judah did according to all that Jehoiada the priest commanded. And they each took his men [who were] {coming off duty on the Sabbath} with {the ones going out to duty on the Sabbath}, for Jehoiada the priest did not dismiss the working groups.