Charles Ellicott Commentary Leviticus 14:6

"As for the living bird, he shall take it, and the cedar wood, and the scarlet, and the hyssop, and shall dip them and the living bird in the blood of the bird that was killed over the running water:" — Leviticus 14:6 (ASV)

And shall dip them and the living bird. — With the crimson thread the priest tied together lengthwise the bundle of hyssop and the cedar wood, extended the wings and tail of the living bird around them, and then dipped all four in the mixture of blood and water which was in the earthen vessel.