Amaziah started out his reign in godliness as his father Joash had done. He appeared to know the law of God. He even heeded the counsel of the prophet regarding his attempt to go to war trusting in Israelite mercenaries rather than the Lord. Yet it became apparent that he obeyed and enforced only those laws and rules which suited his own ends. He seemed to be following God but he was really following the dictates of his own will. This is revealed in his worshipping of the Edomite idols he captured. He did this rather than not give Yahweh the glory for the victory which was due to His strength and faithfulness to Judah. Instead, he felt that victory was his because those idols betrayed Edom and had become his supporters. Therefore the Lord judged him for his unfaithfulness.
There are many politicians, leaders, celebrities and, yes, even pastors who claim to be Christians yet they demonstrate by their actions and attitudes that they are hypocrites. They are in the church but not of the church. They are worldly people who claim to serve God but really use Christianity in a selective manner, obeying those commands which suit their desires or make them look good and honorable, but rejecting those beliefs and standards of Biblical morality that get in their way. For instance there are many who claim to worship Jesus as Lord but support a woman’s right to choose abortion, or the rights of homosexual and others to practice their ungodly proclivities as they desire without being criticized or harassed by believers who call such actions and lifestyles sins. A Christian cannot support God and sin at the same time even if sin is called “civil rights”. Sooner or later, God’s judgment will fall.