Albert Barnes Commentary 2 Kings 22:16

"Thus saith Jehovah, Behold, I will bring evil upon this place, and upon the inhabitants thereof, even all the words of the book which the king of Judah hath read." — 2 Kings 22:16 (ASV)

All the words of the book - The “words” intended here are undoubtedly the threats of the Law, particularly those of Leviticus 26:16-39 and Deuteronomy 28:15-68. Josiah had probably heard only a portion of the Book of the Law, but that portion contained those awful denunciations of coming woe. This explains Josiah’s tearing of his clothes (2 Kings 22:11) and his hurried message to Huldah.