10
When Ahaziah's mother, Athaliah, saw that her son was dead, she began to destroy the entire royal family of the house of Judah.
11
But Jehoshebath, daughter of the king and sister of Ahaziah, took Ahaziah's son Joash. She saved him from being killed with the king's other sons, and she put him and his nurse in a bedroom. Jehoshebath was the daughter of King Jehoram and wife of Jehoiada the priest. Because she was also Ahaziah's sister, she hid Joash from Athaliah. So he wasn't killed.
12
Joash was with the priests. He was hidden in God's temple for six years while Athaliah ruled the country.