Leviticus 14:4; Leviticus 14:7

4 then the priest shall give orders to take two live clean birds and cedar wood and a scarlet string and hyssop for the one who is to be cleansed.

7 "He shall then sprinkle seven times the one who is to be cleansed from the leprosy and shall pronounce him clean, and shall let the live bird go free over the open field.