Leviticus 14:1

This shall be the law of the leper in the day of his cleansing: He shall be brought unto the priest:

And the priest shall go forth out of the camp; and the priest shall look, and, behold, if the plague of leprosy be healed in the leper;

Then shall the priest command to take for him that is to be cleansed two birds alive and clean, and cedar wood, and scarlet, and hyssop:

And the priest shall command that one of the birds be killed in an earthen vessel over running water: