But when he was strong, his heart {i} was lifted up to his destruction: for he transgressed against the LORD his God, and went into the temple of the LORD to burn incense upon the altar of incense.

(i) Thus prosperity causes men to trust in themselves and by forgetting him who is the author of it, procure their own punishment.

Wesley's Notes

26:16 Into Jerusalem - Into the holy place, where the altar of incense stood, and into which none but the priests might enter, much less offer incense.

Jamieson-Fausset-Brown Bible Commentary

2Ch 26:16-21. He Invades the Priest's Office, and Is Smitten with Leprosy.

16-21. he transgressed against the Lord, &c.-(See on [455]2Ki 15:5). This daring and wicked act is in both records traced to the intoxicating influence of overweening pride and vanity. But here the additional circumstances are stated, that his entrance was opposed, and strong remonstrances made (1Ch 6:10) by the high priest, who was accompanied by eighty inferior priests. Rage and threats were the only answers he deigned to return, but God took care to vindicate the sacredness of the priestly office. At the moment the king lifted the censer, He struck him with leprosy. The earthquake mentioned (Am 1:1) is said to have been felt at the moment [Josephus].

Matthew Henry's Concise Commentary

26:16-23 The transgression of the kings before Uzziah was, forsaking the temple of the Lord, and burning incense upon idolatrous altars. But his transgression was, going into the holy place, and attempting to burn incense upon the altar of God. See how hard it is to avoid one extreme, and not run into another. Pride of heart was at the bottom of his sin; a lust that ruins many. Instead of lifting up the name God in gratitude to him who had done so much for him, his heart was lifted up to his hurt. Men's pretending to forbidden knowledge, and seeking things too high for them, are owing to pride of heart. The incense of our prayers must be, by faith, put into the hands of our Lord Jesus, the great High Priest of our profession, else we cannot expect it to be accepted by God, Re 8:3. Though Uzziah strove with the priests, he would not strive with his Maker. But he was punished for his transgression; he continued a leper to his death, shut out from society. The punishment answered the sin as face to face in a glass. Pride was at the bottom of his transgression, and thus God humbled him, and put dishonour upon him. Those that covet forbidden honours, forfeit allowed ones. Adam, by catching at the tree of knowledge which he might not eat of, debarred himself of the tree of life which he might have eaten of. Let all that read say, The Lord is righteous. And when the Lord sees good to throw prosperous and useful men aside, as broken vessels, if he raises up others to fill their places, they may rejoice to renounce all worldly concerns, and employ their remaining days in preparation for death.