2 Kings 23:25
And like unto him was there no king before him, that turned to the LORD with all his heart, and with all his soul, and with all his might, according to all the law of Moses; neither after him arose there any like him. And like unto him was there no king before him, that turned to the LORD with all his heart, and with all his soul, and with all his might, according to all the law of Moses; neither after him arose there any like him.
No king before Josiah and none who arose after him was like him in turning to the Lord with all his heart and soul and might. His devotion was complete and measured by the whole law of Moses, a wholehearted following of God unmatched by any other ruler. Even that faithfulness did not turn away God's great wrath, which remained because of the provocations committed under Manasseh and the deeds by which he had provoked the Lord. Jerusalem's destruction and the people's exile and captivity in Babylon were near, and Jerusalem would soon be utterly destroyed.
His reign stands as a lesson in faithful obedience to God. It highlights determination to walk uprightly. It shows that upright walk maintained despite the wickedness surrounding him.