v1-3: Jehoiada maintained an influence over Joash, even to the choosing of his wives. Jehoiada knew that a son of David had to be king (23.3), and he worked to maintain that dynasty.
v4-5: Not all shared Joash's and Jehoiada's zeal for the things of God; this was negligence rather than rebellion. The money was to be raised from the customary taxation, not from any additional tax, see v9.
v6: Jehoiada was held responsible for the Levites' failure to collect the money to repair the temple; compare Ex 30.12-16.
v7: The testimony of Athaliah; that wicked woman, who had broken into the house of the Lord, and who had presented the dedicated things to the Baals.
The combined influences of Jezebel and Athaliah brought disaster to Israel and Judah; and God had raised up Elijah, Elisha, Jehu, and Jehoiada during this time. Although there were only 15 years between the death of Jehoshaphat and the coronation of Joash. Judah had quickly declined to a dreadful state.
We see God's mercy, that things did not get any worse, and that godly prophets and leaders were raised up, and that the royal line was preserved.
v8-12: It was at Joash's command, following the discovery that the Levites had neglected the collection of the tax, that a chest was placed outside the temple, so that worshippers could pay their tax money. Over a period of time, a great amount of money was collected, and artisans hired to undertake the work to the temple. We read that the people contributed gladly to this work.
v13-14: The temple was restored and reinforced. When things go wrong in our lives, we need to be restored, and it is as well that we learn lessons, and become stronger.
Not only was money brought, but burnt offerings were made, as regular worship continued.
v15-16: The phrases, "all the years of Jehoiada" (v2), "as long as Jehoiada lived" (v14), indicate the priest's influence over Joash. He died aged 130 years, having been born during Solomon's reign. His longevity was another sign of God's mercy to His people.
We may ask whether Joash had relied too much on Jehoiada, or whether Jehoiada had exercised too much influence. There is a balance to be struck between faith in God, and reliance upon a godly man. As we disciple others we must be those that let them serve as God has called them.
Jehoiada was buried with the kings of Judah, reflecting the great good he had done for the nation.
v17-18: After Jehoiada's death, Joash was influenced by others who lacked Jehoiada's godly character. It was not long before Zechariah, Jehoiada's son was killed; mentioned in Matt 23.35. Sadly, that godly influence was soon overturned again.
v19: God sent prophets to Judah, but their message was rejected.
v20: The message of Zechariah. Would Joash not honour the son of Jehoiada?
v21-22: It was by order of Joash that Zechariah was put to death. His dying words, "May the Lord see this and call you to account" were fulfilled, as Joash was defeated by the Arameans.
v23-25: Aram defeated Judah, a small army defeating a much larger one, sine the Lord was punishing the people. The leaders who had influenced Joash were killed. Joash was left wounded, and he was killed by some of his officials.
v26-27: Joash's officials were from Ammonite and Moabite descent.