Albert Barnes Commentary 1 Kings 15:14

"But the high places were not taken away: nevertheless the heart of Asa was perfect with Jehovah all his days." — 1 Kings 15:14 (ASV)

At first glance, 2 Chronicles 14:3 seems to imply that he entirely put down the idolatrous worship. But idolatry, if suppressed at one time, crept back in afterward. It is also possible that while Asa endeavored to sweep it away completely, his subjects would not be controlled and found a means of maintaining it in some places—perhaps not in the cities (see 2 Chronicles 14:5), but in remote country districts where royal authority was weaker and secrecy was more possible.