2 Chronicles 23:4-5

King James Version

⁴ 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;

⁵ 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.