John Gill's Exposition of the Whole Bible
Leviticus 14:6
As for the living bird, he shall take it,.... And dispose of it as after directed; for there was an use for that:
and the cedar wood, and the scarlet, and the hyssop; which were all bound up in one bundle, but whether the living bird was joined to them is a question; according to Jarchi they were separate, the bird by itself, and the cedar wood, c. by themselves they were neither bound together nor dipped together; and Ben Gersom is very distinct and expressive; we learn from hence, says he, that three were bound up in one bundle, but the living bird was not comprehended in that bundle; but according to the Misnah c they were all joined together, for there it is said, he (the priest) takes the cedar wood, scarlet, and hyssop, and rolls them up with the rest of the scarlet thread, and joins to them the extreme parts of the wings and of the tail of the second bird and dips them; and this seems best to agree with the text, as follows:
and shall dip them and the living bird in the blood of the bird [that was] killed over the running water; that is, into the blood of it as mixed with the running water in the earthen vessel, which together made a sufficient quantity for all these to be dipped into it; whether separately, first the living bird, and then the cedar wood, and scarlet, and hyssop, or all together: the bird that was kept alive was a type of Christ, who as a divine Person always alive, and ever will; he is the living God, and impassable: the dipping of this living bird in the blood of the slain one denotes the union of the two natures in Christ, divine and human, and which union remained at the death of Christ; and also shows that the virtue of Christ's blood arises from his being the living God: the dipping of the cedar wood, scarlet, and hyssop, into the same blood, signifies the exercise of the several graces of the Spirit upon Christ, as crucified and slain, and their dealing with his blood for pardon and cleansing, as faith and hope do, and from whence love receives fresh ardour and rigour.
c Ebr. Concord. part. 64. No. 318. Bartenora in ib.