2 Chronicles 22:10-12

10 Now when Athaliah, the mother of Ahaziah, saw that her son was dead, she had all the rest of the seed of the kingdom of Judah put to death.

11 But Jehoshabeath, the daughter of the king, secretly took Joash, the son of Ahaziah, away from among the king's sons who were put to death, and put him and the woman who took care of him in a bedroom. So Jehoshabeath, the daughter of King Jehoram, the wife of Jehoiada the priest and sister of Ahaziah, kept him safe from Athaliah, so that she did not put him to death.

12 And she kept him safe with her in the house of God for six years, while Athaliah was ruling the land.