Komentarz do Diwrej ha-jamim II 34:30

the Scroll of the Covenant All the fright that the king experienced was due to the words (Deut. 28: 36): “The Lord will lead you,” and he saw that the Torah called it a covenant: “These are the words of the covenant.” Therefore, he too enacted a covenant and saw written immediately following it (ibid. 29:8): “And you shall keep the words, etc., and practice them.” Josiah also saw written immediately following (ibid. verses 9ff.): “You are standing today, all of you, etc....your children, your wives...that you should pass into the covenant...enacts with you today.” He said, “In such a manner, I too shall enact a covenant, for there it is written: ‘You are standing, etc.’ I too [will do so], ‘And he caused all those found in Jerusalem, both small and great, to stand.’”

with all his heart and with all his soul as he found written there, (Deut. 30:2): “And you will return to the Lord your God, etc. with all your heart and with all your soul.”