2 Chronicles 12:14 - Joseph Benson’s Commentary on the Old and New Testaments

He prepared not his heart, &c. Directed not, or settled not, &c. That is, although he humbled himself, and seemed penitent for a season, and professed the true religion and worship of God; yet he quickly relapsed into his former sins, because he was not sincere and serious in his actions, and his heart was not right with God. To seek the Lord He did not serve the Lord, because he did not seek the Lord. He did not pray to the Lord, as Solomon did, for wisdom and grace. Or he did not consult the word of God, did not seek to that as his oracle. Hence, what little goodness he had, passed away like the morning cloud, and he did evil because he was not fully determined for that which was good. Those are easily drawn aside to evil by Satan, who are wavering and inconstant in that which is good, and are not persuaded to make religion their business.