Cedar — wood, hyssop, scarlet — All which are here burnt, and as it were offered to God, that they might be sanctified to this holy use for the future; for of these kinds of things was the sprinkle made wherewith the unclean were sprinkled, Leviticus 14:4.
Related Commentaries of Numbers 19:6
Numbers 19:6
6 And the priest shall take cedar wood, and hyssop, and scarlet, and cast it into the midst of the burning of the heifer.