דברי הימים ב, פרק ט״ו, פסוק י״ז

During the reign of King Asa, a complex spiritual reality took hold in the land, creating a sharp divide between the personal conduct of the king and the deeply rooted habits of the public. For generations, the people had grown accustomed to building private altars to worship God. This practice first began during the period between the destruction of Shiloh and the construction of the permanent Temple. Because these altars were dedicated to God rather than to idols, the public felt comfortable using them. However, once the permanent Temple was built, offering sacrifices on private altars anywhere became strictly forbidden and carried a severe punishment, making their continued existence a serious sin [רש״י, מצודת דוד].

Despite the king's broader efforts to purify the land, the private altars were not removed from Israel, and the people continued to sacrifice on them [ביאור שטיינזלץ]. A sharp contrast existed between the nation and its leader [ביאור שטיינזלץ]. While the hearts of the people were not fully devoted to God, Asa remained completely faithful throughout his entire life [מלבי״ם].

The king's complete devotion was clear in his actions. He totally avoided using the private altars. While the common people continued to offer sacrifices locally and kept their dedicated holy items there, Asa took the exact opposite approach. He made sure to bring all of his holy items, as well as those dedicated by his father, directly into the House of God in order to strengthen the central Temple [מלבי״ם].