Either Athaliah thought they were all dead; or if she suspected that Joash was preserved, she thought an infant could do her no great harm; and that she could so well assure the kingdom to herself within a few years, that she need not fear any such weak competitor: or she was willing to smother up the business, lest if she had made a strict and diligent search for it, the people should thereby learn that there was yet a son of David's family left, and so be unquiet under her government, and desirous of a change. Athaliah did reign over the land; which she had an opportunity, to do, because she was not only the late king's wife, but also was probably made queen-regent upon Joram's going to Ramoth-gilead.
Related Commentaries of 2 Kings 11:3
2 Kings 11:3
3 And he was with her hid in the house of the LORD six years. And Athaliah did reign over the land.