The timeline of a monarch's life often reveals more than just dates, serving as a quiet record of pride, punishment, and the gradual decline of a kingdom. The historical record notes a precise overlap between the kings of Israel and Judah. The King of Israel began his rule two years earlier and reigned for sixteen years, meaning the two monarchs ruled at the same time for fourteen years. Since the King of Judah reigned for twenty-nine years in total, exactly fifteen years remained of his life after his rival passed away.
This specific detail about outliving his rival carries a deeper moral message. According to [אברבנאל], highlighting the King of Judah's survival serves to emphasize the downfall of the King of Israel. The Israelite king had previously boasted and mocked his Judean counterpart, arrogantly predicting his defeat in battle. Ultimately, the situation reversed. The boastful king was punished, dying fifteen years before the man he had humiliated.
Yet, these final fifteen years were not a time of triumph or active leadership for the surviving king. [רש"י] clarifies that he did not actually rule during this period. Because he had strayed from God, his son took over the royal duties and governed while his father was still alive.
Looking at his life as a whole, [אברבנאל] notes a tragic pattern, as the king's trajectory mirrored his father's almost exactly. Both men began their reigns as righteous leaders who did what was proper in the eyes of God. However, in their later years, both fell into idolatry, disrespected the prophets sent to guide them, and ultimately suffered devastating defeats on the battlefield as a result.