“The priest shall command, and one shall take for the one being purified two living pure birds, and cedar wood, and scarlet wool, and hyssop” (Leviticus 14:4). “The priest shall command, and one shall take for the one being purified [two living pure birds].” Rabbi Yehuda bar Simon said: These birds are noisy. The Holy One blessed be He said: ‘Let the voice come and atone for the voice.’
Rabbi Shimon ben Levi said: A free bird that eats of his food and drinks his water.21It should be a free bird that lives where it wants and is not confined, and the only benefit it gets from man is food and drink. Is the matter not an a fortiori inference? If birds that eat of his food and drink his water atone for him, a priest who benefits from Israel [by receiving] the twenty-four priestly gifts, all the more so.
The parable says: One who eats hearts of palm will be wounded by the tree trunk.22There is no reward without paying the price. Since the priest benefits from Israel, it is his job to atone for them.