daf bit: Shabbat 56

R. Shmuel b. Nachmani said in the name of R. Yonatan: whoever says that Josiah sinned is in error, for it is said: "and he did what was right in the eyes of the Lord, and walked in all the ways of David his father". But if that is so, how do we interpret "like unto him there was no king before him, that returned to the Lord with all his heart"? If he returned, that means he sinned! No, this teaches that he revised every judgment he made between the age of 8 (when he became king) and 18 (when the scroll of the law was found). He revised prior rulings to be in accord with torah. (56b)

(Today's daf is 57.)