Leviticus 14:7

And he shall sprinkle. — Having thus dipped the hyssop fastened to the cedar stick into the blood and water, the priest is to sprinkle with it the back of the hand and the forehead of the patient seven times. The seven times symbolised the complete cleansing. (See Leviticus 4:6.) Hence Naaman the leper washed himself seven times in the Jordan (2 Kings 5:10; 2 Kings 5:14).

And shall let the living bird loose. — Whereupon the priest not only pronounced the cured man clean and restored to his liberty, but at the same time liberated the bird also. The release of the bird symbolised the freedom restored to the patient, who, like the bird, was now at liberty to go where he liked without any restraint. Because it is here said that the bird is to be let loose “into the open field,” or, more literally, towards the face of the field, the ancient canons decreed that he who lets it loose must not turn his face towards the sea, wilderness, or city, but towards the field. The cedar wood, the crimson thread, and the hyssop, as well as the bird, if caught again, could be used again in the cleansing of other lepers.