II Chronicles​ 26

II Chronicles 26:16: 
But when he was strong, he grew proud, to his destruction. For he was unfaithful to the LORD his God and entered the temple of the LORD to burn incense on the altar of incense.

The tabernacle and the temple were set apart for their holy function, and any trespass against their precincts was sacrilege. When Uzziah the King usurped the office and function of the priest and trespassed on to the priestly ground in the temple, he was smitten with leprosy. The judgment of God in this case as in others had a grim appropriateness: Uzziah having refused to honor that which was set apart by God was himself set apart by leprosy. His sacrilege was followed by his quarantine.

II Chronicles:2:19-23:
Then Uzziah became furious; and he had a censer in his hand to burn incense. And while he was angry with the priests, leprosy broke out on his forehead, before the priests in the house of the Lord, beside the incense altar. 
20And Azariah the chief priest and all the priests looked at him, and there, on his forehead, he was leprous; so they thrust him out of that place. Indeed he also hurried to get out, because the Lord had struck him.
21King Uzziah was a leper until the day of his death. He dwelt in an isolated house, because he was a leper; for he was cut off from the house of the Lord. Then Jotham his son was over the king’s house, judging the people of the land.
22Now the rest of the acts of Uzziah, from first to last, the prophet Isaiah the son of Amoz wrote.
​ 23So Uzziah rested with his fathers, and they buried him with his fathers in the field of burial which belonged to the kings, for they said, “He is a leper.” Then Jotham his son reigned in his place.

Thomas Watson

“As, when king Uzziah would offer incense without a priest, God was angry with him, and struck him with leprosy (2 Chron 26:20). Just so, when we do not come to God in and through Christ, we offer up incense to him without a priest, and what can we expect but severe rebukes?”
― Thomas Watson, The Ten Commandments: The Expansive Commentary Collection

---