Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary

Reign of Ahaziah of Judah (cf. Ch2 22:1-6). - Ahaziah, the youngest son of Joram, ascended the throne in the twenty-second year of his age. The statement in Ch2 22:2, that he was forty-two years old when he became king, rests upon a copyist's error, namely, a confusion of כ twenty with מ forty. Now, since his father became king at the age of thirty-two, and reigned eight years, Ahaziah must have been born in the nineteenth year of his age. Consequently it may appear strange that Ahaziah had brothers still older than himself (Ch2 21:17); but as early marriages are common in the East, and the royal princes had generally concubines along with their wife of the first rank, as is expressly stated of Joram in Ch2 21:17, he might have had some sons in his nineteenth year. His mother was called Athaliah, and was a daughter of the idolatrous Jezebel. In Kg2 8:26 and Ch2 22:2 she is called the daughter, i.e., grand-daughter, of Omri; for, according to Kg2 8:18, she was a daughter of Ahab. Omri, the grand-father, is mentioned in Kg2 8:26 as the founder of the dynasty which brought so much trouble upon Israel and Judah through its idolatry.