Cedar wood, and scarlet, and hyssop. "Cedar wood, and hyssop, and scarlet ' are also to be burnt with the red heifer for the ashes for the water of separation (Numbers 19:6), and they appear to have been commonly employed in purifications (Hebrews 9:19).
The antiseptic properties of cedar made it peculiarly suitable for such occasions. The hyssop "was probably not the plant which we call hyssop, the Hyssopus officinalis. for it is uncertain whether this is to be found in Syria and Arabia, but a species of origanum resembling hyssop, the Arabian zater, either wild marjoram, or a kind of thyme" (Keil on Exodus 12:21).
The Psalmist's cry, "Purge me with hyssop, and I shall be chart" (Psalms 51:7), shows the common use to which it was put. In the present case, the sweet smell both of the wood (one cubit's length of which was used) and of the herb would have still further adapted them for symbolizing the redemption of the leper's flesh from corruption and putrefaction.
The scarlet was probably a band of scarlet wool with which the cedar and the hyssop were tied?봭ot to the bird (for we have no account of their being after, wards removed), but (as in the burning of the red heifer) one to the other.
The colour of the wool was appropriate, not only because it was about to be dipped in the blood and water, but also because it symbolized the purified and now healthy blood.