'Offices' in the Bible

And the priests stood, according to their offices; the Levites also with instruments of music of Jehovah, which David the king had made to give thanks unto Jehovah, (for his lovingkindness endureth for ever,) when David praised by their ministry: and the priests sounded trumpets before them; and all Israel stood.

And he appointed, according to the ordinance of David his father, the courses of the priests to their service, and the Levites to their offices, to praise, and to minister before the priests, as the duty of every day required; the doorkeepers also by their courses at every gate: for so had David the man of God commanded.

besides them that were reckoned by genealogy of males, from three years old and upward, even every one that entered into the house of Jehovah, as the duty of every day required, for their service in their offices according to their courses;

and them that were reckoned by genealogy of the priests by their fathers houses, and the Levites from twenty years old and upward, in their offices by their courses;

And he set the priests in their offices, and encouraged them to the service of the house of Jehovah.