'On the Sabbath' in the Bible

This is the thing which you shall do: one third of you, of the priests and Levites who come in on the sabbath, shall be gatekeepers,

So the Levites and all Judah did according to all that Jehoiada the priest commanded. And each one of them took his men who were to come in on the sabbath, with those who were to go out on the sabbath, for Jehoiada the priest did not dismiss any of the divisions.