Read Leviticus 14:1-20
And the priest shall offer the burnt offering and the meat offering upon the altar: and the priest shall make atonement for him, and he shall be clean. Leviticus 14:20 KJV
Leviticus 13 is discouraging as it talks about the isolation people experienced because of leprosy and other forms of uncleanness, but chapter 14 is encouraging as it describes the eight day process of declaring someone clean who formally had been placed outside the Camp. Imagine the heartache of being declared unclean, and then the opposite emotion of exultation as the priest declared someone clean. The eight day process began with a visit from the priest outside the Camp, and concluded with the person at the Tabernacle with sacrifices being offered for his or her atonement. The offerings included the trespass, sin, wave, burnt, and meal offerings. Once these offerings were made, the sins of the person were forgiven and he or she was then declared clean. According to Hebrews 10, these offerings foreshadowed the work of Christ, in whom we are declared clean from sin.
Lord, being forced to live outside the Camp due to being declared unclean must have been a horrible experience, but then to hear the shout declaring you clean must have been the opposite filling the person with relief, gratitude, and joy. It certainly pictures the experience of salvation when we are declared clean based on your sacrifice.