34:3Meaning
Early seeking, then later purging Josiah’s timeline is set in two steps: in his eighth regnal year, while still young, he begins to seek the God tied to David; in his twelfth year, he begins removing competing worship places and objects from Judah and Jerusalem. The verse frames inner commitment first and then reform activity, and it lists the main targets: high places, Asherim, and different kinds of carved or cast images.
