Rashi on Leviticus 27:27/רש"י על ויקרא כ״ז:כ״ז

1ואם בבהמה טמאה AND IF IT BE OF AN UNCLEAN ANIMAL — This verse does not refer to the firstborn mentioned above (when the translation would be: and if it — the firstborn just mentioned — be בבהמה טמאה, in the category of unclean animals), because one cannot state about the firstborn of an unclean animal: ופדה בערכך “it shall be redeemed by valuation”, since of all unclean animals it is only the firstborn of the ass that has to be redeemed (see Exodus 13:13 and Rashi thereon); and an ass this firstborn spoken of here cannot be, because, you see, the redemption price of the firstborn of an ass is a lamb only, whilst here the animal in question has to be redeemed כערכך, according to a certain valuation; and besides, it (the lamb) is a gift to the priest and is not given to the Sanctuary. But the verse refers to something dedicated to the Temple treasury, being a continuation of v. 11, for that verso above spoke about the redemption of a clean animal which became blemished, and here it speaks about one who dedicates an unclean animal, the proceeds to be used for the Temple repair (Menachot 101a).

2ופדה בערכך THEN HE SHALL REDEEM IT ACCORDING TO THE VALUATION — i. e. according as the priest will estimate its value.

3ואם לא יגאל OR IF IT BE NOT REDEEMED by the owners,

4ונמכר בערכך THEN IT SHALL BE SOLD ACCORDING TO THE VALUATION to others (Sifra, Bechukotai, Chapter 12 2).