1 Kings 15:10

And forty and one years reigned he in Jerusalem. And his mother’s name was Maachah, the daughter of Abishalom.

The verse stands in the larger account of Israel's apostasy, in which her kings led the nation to forsake the worship of the living God and to turn to the worship of idols, turning away from the God-given plan of worship which pointed to Christ and revealed the way of salvation from sin, forsaking all that was pure and true and uplifting to turn to the worship of Baal and Ashtoreth, to that which was impure, untrue, and degrading, to the worship of the creature instead of the Creator. It belongs to the account of Asa's reign in Judah after the brief, wicked reign of Abijam, also called Abijah, in the time after the kingdom was divided into Judah and Israel when there was war and strife between the two divisions. That reign was better and largely for the better.

The verse records that Asa reigned forty and one years in Jerusalem, beginning when about twenty years old despite having a bad father, a bad grandfather, a bad grandmother Maachah, and heathen influences on every side. His forty-one-year reign as king of Judah in Jerusalem was one good reign that spanned the reigns of all the wicked kings of Israel from Jeroboam onward, since Asa came to the throne two years before the death of Jeroboam. It was a good reign that brought prosperity to Judah under his rule, and the reforms he effected were far-reaching.

The long reign began with doing good and trusting in God and restoring the worship of the true God by removing and destroying strange gods, breaking down images, cutting down groves, removing the wicked queen-mother from her position of dignity and influence, and commanding Judah to serve God. For ten years the kingdom had rest, in which he stayed faithful through the testing time of peace, and when Zerah the Ethiopian invaded he cried to the Lord as the only helper and the Lord smote the Ethiopians before him in answer to his prayer of faith. Though the latter part of the forty-one years was marred by lack of trust in God, the account of his reign in Judah is described more fully in Chronicles.