Divrey Hayamim Bais 34:3

3 For in the eighth year of his reign, while he was yet na’ar (young), he began to seek after Elohei Dovid Aviv; and in the twelfth year he began to make tahor Yehudah and Yerushalayim from the high places, and the Asherim, and the pesilim, and the massekhot (molten images).

Divrey Hayamim Bais 34:3 Meaning and Commentary

2 Chronicles 34:3

For in the eighth year of his reign, while he was yet young,
&c.] Being in the sixteenth year of his age; though Kimchi thinks it was the very year he began to reign, which was the eighth of his age; and Jarchi observes, it may be interpreted, "though he was young, he began to seek after the God of David his father"; to pray unto him, to seek after the knowledge of him, and the true manner of worshipping him, what were his will, commands, and ordinances; the Targum is,

``to seek instruction or doctrine of the Lord God of David his father,''

to be taught his ways, such as David his great ancestor walked in, and whom he chose to follow:

and in the twelfth year he began to purge Judah and Jerusalem from the
high places, and the groves and the carved images, and the molten
images;
which were made in the times of Manasseh; and though removed by him when humbled, were restored in the reign of Amon. Now Josiah purged the land from these, by putting them down, and destroying them; and this he did when he was twenty years of age, having now more authority, being out of his minority, and from under guardians, and one year before Jeremiah began to prophesy, ( Jeremiah 1:1-2:37 ) .

Divrey Hayamim Bais 34:3 In-Context

1 4 Yoshiyahu was 8 years old when he began to reign, and he reigned in Yerushalayim 31 shanah.

2 And he did that which was yashar in the eyes of Hashem, and walked in the ways of Dovid Aviv, and veered off neither right nor left.

3 For in the eighth year of his reign, while he was yet na’ar (young), he began to seek after Elohei Dovid Aviv; and in the twelfth year he began to make tahor Yehudah and Yerushalayim from the high places, and the Asherim, and the pesilim, and the massekhot (molten images).

4 And they demolished the mizbechot of Ba’alim in his presence; and the incense stands erected above them he smashed; and the Asherim, and the pesilim, and the massekhot he demolished and made dust of them, and scattered upon the keverim (graves) of them that had sacrificed unto them.

5 And he burned the atzmot of the Kohanim upon their mizbechot, and made tahor Yehudah and Yerushalayim.