2 Chronicles 23:4-5

This {is} the thing that ye shall do; A third part of you entering on the sabbath, of the priests and of the Levites, {shall be} porters of the doors; {doors: Heb. thresholds} And a third part {shall be} at the king's house; and a third part at the gate of the foundation: and all the people {shall be} in the courts of the house of the LORD.