2 Kings 11:2-6

But Jehosheba, the daughter of King Joram, sister of Ahaziah, took Joash the son of Ahaziah and abducted him from among the king’s sons who were being put to death, and put him and his nurse in the bedroom. So they hid him from Athaliah, and he was not put to death.

So he was kept hidden with her in the house of the Lord for six years, while Athaliah was reigning over the land.

Now in the seventh year Jehoiada sent orders and brought the captains of hundreds of the Carites and of the guards, and brought them to himself at the house of the Lord. Then he made a covenant with them and put them under oath at the house of the Lord, and showed them the king’s son.

And he commanded them, saying, “This is the thing that you shall do: a third of you, who come in on the Sabbath and keep watch over the king’s house

(a third also shall be at the gate Sur, and a third at the gate behind the guards), shall keep watch over the house for defense.