2 Chronicles 26:16

16But when Uzziah became strong, he became so proud [of himself and his accomplishments] that he acted corruptly, and he was unfaithful and sinned against the Lord his God, for he went 26:16 Only priests were permitted to enter the temple proper and perform such ceremonies.into the temple of the Lord to burn incense on the altar of incense. [Num 3:38]