He was twenty-five years old when he became king, and he reigned in Jerusalem twenty-nine years. His mother’s name was Abi, the daughter of Zechariah.
We have here a general account of the reign of Hezekiah. It appears, by comparing his age with his father's, that he was born when his father was about eleven or twelve years old, divine Providence so ordering that he might be of full age, and fit for business, when the measure of his father's iniquity should be full. Here is, I.
Commenting on 2 Kings 18:1-8
Twenty and five years old was he when he began to reign,.... Now as Ahaz his father began to reign at twenty, and reigned sixteen, he must die at thirty six; so that this son of his must be born to him when at eleven years of age, for only so many years there be between twenty five and thirty six, which may seem wonderful...
So these nations feared the LORD, and served their graven images, both their children, and their children's children: as did their fathers, so do they unto this day. (t) That is, these strangers who were sent into Samaria by the Assyrians.
Commenting on 2 Kings 18:1-2