Birds, Cedar, Yarn, and Hyssop

Leviticus 14:1-7 - The LORD said to Moses, "These are the regulations for the diseased person at the time of his ceremonial cleansing, when he is brought to the priest: The priest is to go outside the camp and examine him. If the person has been healed of his infectious skin disease, the priest shall order that two live clean birds and some cedar wood, scarlet yarn and hyssop be brought for the one to be cleansed. Then the priest shall order that one of the birds be killed over fresh water in a clay pot. He is then to take the live bird and dip it, together with the cedar wood, the scarlet yarn and the hyssop, into the blood of the bird that was killed over the fresh water. Seven times he shall sprinkle the one to be cleansed of the infectious disease and pronounce him clean. Then he is to release the live bird in the open fields.

I wonder why these 4 items (see heading) were chosen as part of the cleansing ceremony. I'm sure someone has figured out the reasons why or the symbolism, if any, involved, but I'm pretty sure I've never had it explained to me before.

I'm curious. Could you please tell me what brought you to this page by mentioning it ina comment? I won't publish the comment, if you ask me not to.