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.