John Gill Commentary 2 Chronicles 22:11

"But Jehoshabeath, the daughter of the king, took Joash the son of Ahaziah, and stole him away from among the king`s sons that were slain, and put him and his nurse in the bedchamber. So Jehoshabeath, the daughter of king Jehoram, the wife of Jehoiada the priest (for she was the sister of Ahaziah), hid him from Athaliah, so that she slew him not." — 2 Chronicles 22:11 (ASV)

(See Gill on 2 Chronicles 22:9).