Tearing the clothes, messing the hair, and covering the upper lip were all signs of mourning (cf. Leviticus 10:6; Leviticus 21:10; Genesis 37:34; Numbers 14:6; 2 Samuel 1:11; 2 Kings 11:14; 2 Kings 19:1; 2 Kings 22:11; 2 Kings 22:19; Ezra 9:5; Ezekiel 24:17; Ezekiel 24:22; Micah 3:7). Not every place outside the camp was unclean; there were clean places outside the camp (e.g, Leviticus 4:12). However the unclean person was to live in an unclean area outside the camp. The idea was that he or she could not come close to God who resided in the tabernacle at the center of the camp. [source][source][source]
"The holiest area, where one was closest to God, was the tabernacle. It was here that the holy men, the priests, worked. The tabernacle was surrounded by the camp where Israel the holy people of God lived. This in turn was encircled by the area outside the camp. which was populated by non-Jews, sinners, and the unclean. To live outside the camp was to be cut off from the blessings of the covenant. It is little wonder that when a man was diagnosed as unclean he had to go into mourning. He experienced a living death; his life as a member of God"s people experiencing God"s blessing came to an end. Genesis 3presents a similar picture.... As Adam and Eve experienced a living death when they were expelled from Eden, so every man who was diagnosed as unclean suffered a similar fate." [1][source]
". . . as human skin was the focus of guilt and shame in the beginning, so now diseases of the skin provide an occasion to demonstrate the need for human cleansing. In other words, just as the effects of the first sin were immediately displayed in human skin ("And their eyes were opened and they knew that they were naked," Genesis 3:7), so the writer uses the graphic horror of skin diseases found in these texts to depict the human state of uncleanness before a holy God. [source][source][source]
"According to the regulations in Leviticus , if one were found to be unclean, "As long as he has the infection he remains unclean. He must live alone; he must live outside the camp" ( Leviticus 13:46). In the same way, the Genesis narratives show that when Adam (and Eve) sinned, "the LORD God banished him from the Garden of Eden to work the ground from which he had been taken. And he drove Adam out" ( Genesis 3:23-24). Like the unclean person in Leviticus , they had to live "outside the camp."" [2][source]
"Holiness in Leviticus is symbolized by wholeness. Animals must be perfect to be used in sacrifice. Priests must be without physical deformity. Mixtures are an abomination. Men must behave in a way that expresses wholeness and integrity in their actions. When a man shows visible signs of lack of wholeness in a persistent patchy skin condition, he has to be excluded from the covenant community. Temporary deviations from the norm do not attract such treatment, but if the symptoms last for more than two weeks, he must go to live outside the true Israel.... Anyone might fall victim to these complaints and face the prospect of being cut off from his family and friends for the rest of his days. Yet it was considered so important to preserve the purity of the tabernacle and the holiness of the nation that individuals and families might be forced to suffer a good deal. Individual discomfort was not allowed to jeopardize the spiritual welfare of the nation, for God"s abiding presence with his people depended on uncleanness being excluded from their midst (cf. Isaiah 6:3-5)." [3][source]
The Israelites evidently regarded "leprosy" as representing sin. It resulted in the leper"s separation from God and from other people. In many respects leprosy and sin were similar in both their character and consequences. [source][source][source]
"Before the people of God can enter the presence of the holy God they must be free of all disease.... Bodily diseases are incompatible with the holy presence of the LORD." [4][source]
The sacrifice of Jesus Christ has made it possible for us to enter God"s presence (cf. Isaiah 53:5 : "By His scourging we are healed [5]"). [source][source][source]
"In the church today no rule prevents people with skin diseases from entering the place of worship, because it is simply an assembly of believers and not the sanctuary with the holy of holies and the actual dwelling of the glory of the LORD. Yet common sense should tell someone with a contagious illness to remain at home or in the hospital. That is the practical side of Leviticus. Nevertheless, the theological understanding behind any illness is that it is part and parcel of the fallen condition of human life in this world." [6][source]