2 Kings 21:8
Neither will I make the feet of Israel move any more out of the land which I gave their fathers; only if they will observe to do according to all that I have commanded them, and according to all the law that my servant Moses commanded them.
God pledged that He would not cause the feet of Israel to move any more out of the land He had given to their fathers, but only on the condition that they would observe to do according to all that He had commanded them and according to all the law that His servant Moses had commanded them. The statutes they were to keep were those recorded by Moses, especially those contained in the book of the covenant in Deuteronomy. Those statutes were to be made plain through teaching priests who read them publicly each day, and careful observance of them is what made the reign of Hezekiah prosperous.
Manasseh dared to set these statutes aside in direct defiance of the condition for remaining in the land. During his reign the temple copy of the book of the law was lost through careless neglect. For many years as a result the people were deprived of its instruction. That unfaithfulness brought threatened judgments pointing toward Babylonian captivity. Those judgments were averted for a season by the reformation that took place in the eighteenth year of Josiah.