Two birds (probably sparrows) were used in the cleansing ceremony of a leper according to Leviticus 14.4. A priest killed one of the birds in an earthenware vessel over running water. The bird that was kept alive was then dipped in the blood of its fellow, together with cedar wood, scarlet and hyssop. The healed leper was then sprinkled with the blood while the living bird was released.
This purification ritual is referred to by Jesus when he said to the cleansed leper, “Go thy way, shew thyself to the priest, and offer the gift that Moses commanded for a testimony unto them” (Matt. 8. 4).