He did that which was right - He began his reign well, but soon became an idolater, 2 Chronicles 25:14, 2 Chronicles 25:15.

but not

2 Chronicles 25:14 Now it came to pass, after that Amaziah was come from the slaughter of the Edomites, that he brought the gods of the children of Seir...

2 Chronicles 24:2 And Joash did that which was right in the sight of the LORD all the days of Jehoiada the priest.

2 Chronicles 26:4 And he did that which was right in the sight of the LORD, according to all that his father Amaziah did.

1 Samuel 16:7 But the LORD said to Samuel, Look not on his countenance, or on the height of his stature; because I have refused him...

2 Kings 14:4 However, the high places were not taken away: as yet the people did sacrifice and burnt incense on the high places.

Psalm 78:37 For their heart was not right with him, neither were they steadfast in his covenant.

Isaiah 29:13 Why the Lord said, For as much as this people draw near me with their mouth, and with their lips do honor me...

Hosea 10:2 Their heart is divided; now shall they be found faulty: he shall break down their altars, he shall spoil their images.

Acts 8:21 You have neither part nor lot in this matter: for your heart is not right in the sight of God.

James 1:8 A double minded man is unstable in all his ways.

James 4:8 Draw near to God, and he will draw near to you. Cleanse your hands, you sinners; and purify your hearts, you double minded.

The Unmerciful Servant.
"Therefore is the kingdom of heaven likened unto a certain king, which would take account of his servants. And when he had begun to reckon, one was brought unto him, which owed him ten thousand talents. But forasmuch as he had not to pay, his lord commanded him to be sold, and his wife, and children, and all that he had, and payment to be made. The servant therefore fell down, and worshipped him, saying, Lord, have patience with me, and I will pay thee all. Then the lord of that servant was moved …
William Arnot—The Parables of Our Lord