Leviticus 14:7

Seven times - The seal of the covenant, expressed in the number seven (compare Leviticus 14:9), was renewed in sprinkling him who, during his leprosy, had lived as an outcast. The details of a restoration to health and freedom appear to be well expressed in the whole ceremony. Each of the birds represented the leper. They were to be of a clean kind, because they stood for one of the chosen race. The death-like state of the leper during his exclusion from the camp was expressed by killing one of the birds. The living bird was identified with the slain one by being dipped in his blood mixed with the spring water that figured the process of purification, while the cured leper was identified with the rite by having the same water and blood sprinkled over him. The bird then liberated was a sign that the leper left behind him all the symbols of the death disease and of the remedies associated with it, and was free to enjoy health and social freedom with his kind. Compare Colossians 2:12.