2 Kings 11:3-5
English Standard Version
4But in the seventh year Jehoiada sent and brought the captains of the Carites and of the guards, and had them come to him in the house of the Lord. And he made a covenant with them and put them under oath in the house of the Lord, and he showed them the king 's son.
5And he commanded them, "This is the thing that you shall do: one third of you, those who come off duty on the Sabbath and guard the king 's house
