In the biblical context, the concepts of cleanness and uncleanness are deeply rooted in the laws and teachings found primarily in the Old Testament. These laws were given to the Israelites to distinguish them as a holy people set apart for God. The regulations concerning cleanness and uncleanness cover various aspects of daily life, including dietary laws, physical conditions, and moral behavior.

Dietary Laws

The dietary laws, as outlined in Leviticus 11 and Deuteronomy 14, provide specific guidelines on which animals are considered clean and unclean. Clean animals, which the Israelites were permitted to eat, include those that have a divided hoof and chew the cud, such as cattle, sheep, and goats. In contrast, animals that do not meet these criteria, such as pigs and camels, are deemed unclean. Leviticus 11:7-8 states, "And the pig, though it has a divided hoof, does not chew the cud; it is unclean for you. You must not eat their meat or touch their carcasses; they are unclean for you."

Physical Conditions

The laws of cleanness and uncleanness also address various physical conditions, including skin diseases, bodily discharges, and contact with dead bodies. Leviticus 13 and 14 provide detailed instructions for diagnosing and cleansing skin diseases, commonly referred to as leprosy in biblical texts. A person with a skin disease was considered unclean and required to live outside the camp until declared clean by a priest. Leviticus 13:45-46 states, "The diseased person must wear torn clothes and let his hair hang loose, and he must cover his mouth and cry out, 'Unclean, unclean!' As long as he has the infection, he remains unclean. He must live alone in a place outside the camp."

Bodily discharges, whether from a man or a woman, also rendered a person unclean. Leviticus 15 provides guidelines for handling such situations, emphasizing the need for purification rituals. For example, Leviticus 15:19 states, "When a woman has a discharge and the discharge from her body is blood, she shall be in her menstrual impurity for seven days, and anyone who touches her will be unclean until evening."

Moral and Spiritual Implications

Beyond physical and dietary regulations, the Bible also addresses moral and spiritual cleanness. The prophets often used the language of cleanness and uncleanness to call the people of Israel to repentance and holiness. Isaiah 1:16-17 exhorts, "Wash and cleanse yourselves. Remove your evil deeds from My sight. Stop doing evil! Learn to do right; seek justice and correct the oppressor. Defend the fatherless and plead the case of the widow."

In the New Testament, Jesus Christ emphasized the importance of inner purity over external rituals. In Mark 7:18-23 , Jesus taught, "Are you still so dull? Do you not see that nothing that enters a man from the outside can defile him, because it does not enter his heart, but it goes into the stomach and then is eliminated?" (Thus all foods are clean.) He continued: "What comes out of a man, that is what defiles him. For from within the hearts of men come evil thoughts, sexual immorality, theft, murder, adultery, greed, wickedness, deceit, debauchery, envy, slander, arrogance, and foolishness. All these evils come from within, and these are what defile a man."

Ritual Purification

The process of becoming clean after being declared unclean often involved specific rituals, including washing with water, offering sacrifices, and waiting for a designated period. These rituals served as a means of restoring the individual to a state of ceremonial purity, allowing them to participate fully in the religious and communal life of Israel. For instance, Numbers 19 describes the use of the ashes of a red heifer mixed with water for purification from contact with a dead body.

The laws of cleanness and uncleanness underscore the holiness of God and the need for His people to live in a manner that reflects His purity and righteousness. These regulations, while specific to the covenant community of Israel, point to the broader biblical theme of God's desire for His people to be holy as He is holy.