The succession of a new king in Judah brings with it a fascinating historical puzzle. The recorded ages suggest an impossible reality where the new king is two years older than his father. The father passed away at the age of forty, yet the son takes the throne at forty-two. Furthermore, other historical records indicate the son was actually twenty-two when his reign began. Adding to the mystery, the new king's mother is identified by her grandfather's name rather than her father's.
To resolve the timeline, the primary approach among commentators is that the age of forty-two does not reflect the king's actual biological age, but rather serves as a historical marker [ביאור שטיינזלץ]. This number represents a span of forty-two years from the moment a severe decree of destruction was issued against the royal house of David. This countdown began when a previous king of Judah married into the royal family of Israel, founded by Omri. Because the new king of Judah ultimately met his end alongside the king of Israel, the years of his reign are forever linked to the downfall of Omri's dynasty [רש״י, מצודת דוד, רד״ק].
Others find this historical calculation too distant from a simple reading of the events and offer alternative explanations. One view suggests that the father actually lived much longer than forty years. However, his final years were plagued by severe illness and defeats by enemies, so they were stripped from his official royal record. The son was indeed crowned at twenty-two while his father was still alive, and by the time his father finally died, the son was forty-two [רד״ק]. Another perspective resolves the timeline by connecting the events directly to the father's illness, suggesting the number forty actually refers to the father's age when he fell ill and his son first assumed control [מלבי״ם].
Regarding the length of his rule, the records state he governed independently for only a single year. In reality, he had already been managing the kingdom's affairs for a year or two while his father was incapacitated by illness. It was only after his father's death that he held absolute, independent authority for one final year [רש״י, רד״ק, מלבי״ם].
Finally, the royal mother is introduced as the daughter of Omri, even though other accounts clearly identify her as the daughter of Ahab, Omri's son. Commentators explain that it is common in biblical history for grandchildren to be referred to as children of their grandparents [רד״ק, מצודת דוד]. It is also possible that Omri personally raised her, earning her the title of his daughter [מצודת דוד]. Alternatively, the name simply identifies her broader family affiliation, as the entire royal lineage of Israel was commonly named after Omri, its founding father [ביאור שטיינזלץ].