מלכים ב, פרק כ״ב, פסוק א׳

Josiah assumed the throne of Judah as a mere child of eight, yet his righteous character and deep devotion were evident from the very beginning of his reign. His young age at the time of his coronation provides unexpected insight into the timeline of his father, Amon. Because Amon died at the age of twenty-four, he must have married and fathered Josiah when he was only about fifteen years old, or perhaps even younger [ביאור שטיינזלץ].

Even though Josiah was thrust into leadership during his youth, his early actions clearly revealed his true nature. From his earliest days, he chose to do what was right in the eyes of God, modeling his life after David. David is considered his father in a spiritual sense, as Josiah held firmly to the same path and the same deep fear of God that defined David's life [אברבנאל].