In Judah: Judah's leaders once again depart from the truth. Jehoiada had provided a great deal of strength and encouragement. The nation respected the results of his work. But as is so often the case, the other leaders didn't appreciate the means to that end—obedience to God—and soon sank back into idolatry. Again, God took action to show them how wrong they were. He had warned them through Moses about what would happen (Leviticus 26:17; compare verse 8).
The really sad part of the story is that of King Joash. From the time he came to the throne as a seven-year-old boy, Jehoiada had been almost an adoptive father to him, even having chosen his wives (2 Chronicles 24:3). And Joash had done so well in restoring proper worship in Judah. Yet he "comes across as a man of weak character. As long as Jehoiada lived, he followed the Lord. But with the priest gone, the king was just as easily led into sin. The measure of our children's character is not how they behave while they are at home, but the choices they make after they leave!" (Bible Reader's Companion, note on verse 17). Incredibly, the king, who had been like a son to Jehoiada, ended up killing Jehoiada's actual son for giving advice he didn't like. This was his own cousin (2 Chronicles 22:11; 2 Chronicles 24:20). "This once-good king had sunk to the level of his evil grandmother Athaliah (see 2 Chronicles 22:10), despite decades of past faithfulness to God" (Nelson Study Bible, note on verse 24).
This should serve as a warning to us all. In the end, Joash was murdered. But he "was excluded from the royal cemetery because he fell far short of the Davidic ideal (see 2 Chronicles 21:20). Ironically, Jehoiada, who was not a king at all, was buried among the kings because of his faithfulness to God and to God's chosen king (v. 16)" (same note). There are other examples in Scripture of apostasy following the removal of an influential righteous figure. The apostle Paul, for instance, knew that apostasy would follow his own death. And sadly, this pattern has persisted.
In Israel: While Joash was starting to rebuild the temple in Judah, Jehoahaz was coming to the throne in Israel. But his rule was nothing like what was happening in Judah. Jehoahaz continued in the sins of Jeroboam, as Jehu had. The reduction of Israel's power as divine punishment was severe (see 2 Kings 13:7), "a far cry from the time when Ahab alone could muster two thousand chariots for the allied forces at Qarqar" (The Expositor's Bible Commentary, note on verse 7).
The next king of Israel was Jehoash (or Joash) and he too persisted in wrongdoing. In 2 Kings 13:14, "Jehoash's cry over the aged Elisha repeats the words of Elisha spoken when Elijah was taken up to heaven (2 Kings 2:12). Thus, both at the beginning of his ministry and at its conclusion, Elisha is unmistakably linked to his mentor Elijah. The grief of Jehoash at the impending death of Elisha shows that, like his father Jehoahaz (see vv. 4, 5), this Israelite king possessed some genuine spirituality. The line of Jehu had its good moments and received some reward from the Lord (see 2 Kings 10:30). However, none of this line or any other of the kings of Israel served God with all their heart (see 2 Kings 10:31)" (Nelson, note on 2 Kings 13:14).
A slightly different take on Jehoash's grief is explained the The Bible Reader's Companion: “Even the wicked king Jehoash wept at the death of Elisha, but only because he was a national resource; the equivalent of a chariot army! Yet even this cry shows a lack of faith. Elisha died [or, at this point, was dying]. But God lived [—a point illustrated by the miracle of Elisha's bones].... Let's not make the mistake of trusting in God's ministers, and not in God" (note on verse 16).
Elisha's Last Signs
Before his death, Elisha asked Jehoash to shoot an arrow and then to strike some arrows on the ground. "This section describes a symbolic act that Elisha had Joash perform to ensure victories over his enemies; the king was only partly successful in completing the task. Elisha's symbolic act of putting his hands on the king's hands should have alerted the king that the aged prophet was conveying a divine blessing on him. Jehoash's halfhearted compliance with Elisha's instructions exposed his weak faith and illustrated God's unfavorable evaluation of his character (2 Kings 13:11). God's dying prophet was rightly disturbed. Although God would allow Israel to defeat the Aramean army three times, their victory would be incomplete" (Nelson, note on verses 15-19).
After this, Elisha died. But the miracles associated with him didn't stop. God had one more dramatic sign: the raising of a dead man who came in contact with Elisha's remains. "There was no magic in Elisha's bones, but a demonstration of the power of God associated with his servant" (note on 2 Kings 13:21). "The juxtaposition of this event with the account that precedes it makes it clear that herein was another divinely intended sign for Jehoash and Israel; God was the God of the living, not the dead (cf. Luke 20:38), not only for Elisha [who would one day be resurrected] and the man who had [now] been restored to life, but for Israel as well. Israel could yet 'live' if she would but appropriate the eternally living God as her own. The entire episode was, further, a corroborative sign that what Elisha had prophesied would certainly come to pass. Only a living God could guarantee such a thing (cf. Isa 44)" (Expositor's, note on 2 Kings 13:21). "This miracle should have reassured Jehoash that God intended to rescue Israel from the deadly grip of Aramean domination (see v. 25)" (Nelson, note on verse 21).
"In accordance with Jehoash's striking the ground three times with arrows (2 Kings 13:18), God gave Jehoash victory over the Arameans only three times. Yet God graciously overruled Jehoash's inadequate faith by granting Israel full victory over the Arameans during the reign of his son Jeroboam II" (note on verse 25).