2Chr. 24:1 Joash was seven years old when he became king, and he reigned in Jerusalem forty years. His mother’s name was Zibiah; she was from Beersheba.
2Chr. 24:2 Joash did what was right in the eyes of the LORD all the years of Jehoiada the priest.
Joash was a young boy when he started ruling over Judah that’s why he needed a mentor. He did a lot of reforms including the repair of the temple. He did what was right in the eyes of God as Jehoiada the priest instructed him. Joash did a lot that was good. But he did not go far enough. The high places were still there and the people continued to sacrifice to idols.
2Chr. 24:17 After the death of Jehoiada, the officials of Judah came and paid homage to the king, and he listened to them.
2Chr. 24:18 They abandoned the temple of the LORD, the God of their fathers, and worshiped Asherah poles and idols.
As long as Jehoiada was living, Joash served the Lord but when the priest died, Joash started to drift away and worship idols. He started listening to the advice of bad people. We must be careful to choose who we listen to for advice. We need to surround ourselves with godly men who will give us good counsel.
In the end, Joash was killed by his own officials who plotted against him.
2Chr. 24:25 When the Arameans withdrew, they left Joash severely wounded. His officials conspired against him for murdering the son of Jehoiada the priest, and they killed him in his bed. So he died and was buried in the City of David, but not in the tombs of the kings.
As leaders, we must have the tenacity to follow through. Its not how we start that’s more important but its how we finish the race. We cannot just ride on our past successes and stay in our status quo. Joash started something very noble and had great intentions. But in the end, his life was the total opposite of what he started. It was good (start) but not good enough (finish).

Source: Faith