More rules about skin diseases, including leprosy and other infections even mould in houses. Its quite sophisticated to connect mould in dwellings to disease, and the instructions for fixing it make a lot of practical sense. In england as late as the 1800s, for example, they didn’t have such a clear notion of the connection, I think.
But in this chapter, about the circumstances of disease being declared gone, not diagnosis as in the last chapter, there is more of a religious element. So we blend practical advice with rules about recognition of god in response to being clean. Its interesting, getting sick was not seen as a metaphor for exceptional sin, and Jesus repeated that notion in his teaching, but being cured is a metaphor for also being cured of sin.
Jesus’ healing of lepers reaches back to these rules, in fact he sent his healed lepers to the temple to be declared clean, which is a ritual very similar to the ordination of the priests, quite a life changing bond of the person to god, being anointed with oil.
That particular miracle would should have had great power and significance for the priests as evidence of Jesus’ divinity, and arguably the connection was made by god in this chapter just for that moment.
Again, heartening practical exceptions for the poor. Reading this in the week that D S Trump announced a budget gutting services for the poor, in a world where inequality and poor-blaming seem to be on the rise.
The message of “clean and unclean” is firstly that its not individually blameworthy to be unclean – Jesus would ultimately argue that the reason for the law is to show that we are all equally unclean in God’s sight, not to weed out the failures – everyone from priest to leper is unclean. There is no favoured group. Secondly, God makes clean. So being unclean is inevitable, like breathing, and cleansing is an act of God’s grace.