Parshas Metzora begins with the purification of the Metzora, the sufferer from the spiritual disease known as Tzaras. The Metzora's partner in the purification ritual is the Kohen and though the two men seem far apart, one a pariah who must shout his uncleanliness to the world, and the other, a priest who is obligated to maintain a high level of purity, the rituals have a similarity to them.
Like the Levi, the Metzora's hair is shaved off. Like the Kohen's ritual with blood, oil is placed on his ear, thumb and foot. The very ritual requires an encounter between the Kohen, who is required to maintain ritual purity, and the Metzora, who is the embodiment of ritual impurity, and the former subjects the latter to a ritual similar to that undergone by the original Kohanim.
The Kohen and the Metzora are both set apart from the community. Both are displaced from the conventional life of the community. The Kohen's role reserves him for a higher function. The Metzora has fallen through the cracks at the bottom. It's easy to see them as people who should never meet.
And yet it is the Kohen, who must maintain purity to serve G-d, who welcomes back the Metzora.
The rituals of the Kohen are not so different in some ways from that of the most disgraced and lowest individual among the Jewish people. Like the Metzora, the Kohen has to struggle to rise and atone. Holiness is a challenge for him as it was for the Metzora and as it is for any Jew. The purification ritual ends the Metzora's period of disgrace by honoring him with a meal offering with oil. It concludes with the Kohen anointing the Metzora with oil.
The Metzora has made the journey from uncleanliness to being the central figure in a divine service conducted by a Kohen. The Kohen is meant as a role model for the Metzora. And this would not be possible if the Kohen insisted on having nothing to do with the Metzora.
Just as the ritual is a lesson to the Metzora, that repentance can allow him to rise to being anointed by a priest of G-d, it is also a lesson to the Kohen that it is the role of Jewish leaders to reach out even to the most "unclean".
The Metzora is shown that in repentance he can have a shadow of the glory of the Kohen. While the Kohen is reminded that he may not be too different from the Metzora. Both rise in the service of G-d.
And both can fall.
The Metzora suffered his punishment for shattering the harmony of the community with his malicious behavior. The Kohen is called on to repair that harmony by returning him to it. Purification allows objects to be restored to homes, houses to be occupied and people to rejoin their communities.
Purification heals the fabric of the community.
The rule of Tumah Hutra Be'Tzibbur states that even when the entire congregation is impure, the Korban Pesach is still brought because "impurity is permitted in a congregation". When everyone is impure, it is more important to still maintain unity in the service of G-d. Under those conditions, even impurity becomes permissible.
Likewise even the Kohen Gadol is expected to bury a Met Mitzvah, an unknown corpse whom no else is available to bury. Though Kohanim have very strict requirements of purity, they are expected to transgress them when it comes to restoring a lost person to the community, even when he is no longer among the living.
The entire story of the Metzora would seem to be a narrative of exclusion. A pariah is driven out of the community. Forced to avoid people. Humiliated and disgraced. And yet the true lesson is the exact opposite of that. It is not a story of exclusion, but inclusion. It is the Metzora who attempted to exclude others from the community through slander. And it is the Kohen who restores him to it while showing him an example of inclusiveness and healing.