'Office' in the Bible

For the Levites left their suburbs and their possession, and came to Judah and Jerusalem: for Jeroboam and his sons cast them off, that they should not execute the priest's office unto Jehovah;

And under him were Eden, and Miniamin, and Jeshua, and Shemaiah, Amariah, and Shecaniah, in the cities of the priests, in their office of trust, to give to their brethren by courses, as well to the great as to the small:

and them that were reckoned by genealogy of all their little ones, their wives, and their sons, and their daughters, through all the congregation: for in their office of trust they sanctified themselves in holiness.