And if it be any unclean beast. Moses now, in the second place, treats of brute animals; which God commands to be sacrificed to Him, if they are suitable for it, and does not suffer the vow to be altered. But if they be imperfect or unclean, He lays down the rule for their redemption. But the question here arises, How it can be allowable to vow what God had forbidden to be offered to Him, and so had prohibited from being brought into the temple, as being unclean? Surely if it had entered into any one's mind to sacrifice an unclean animal, the superstition would be rejected, nay, there would be need of expiation. But here, in my opinion, another kind of offering is adverted to, which did not vitiate the sacrifices and service of God by being contrary to the injunctions of His Law. There was therefore nothing strange in His accepting such a vow, though He punishes its levity by a pecuniary fine. Besides, suppose a strong and well-tried horse was in danger, his master made a vow that if it were saved he would be bound to pay its price; and so also in the other cases. To vow was nothing else than to commit to God's faithfulness and protection whatever they wished to be preserved. Hence the too great commonness of vows, which still it was necessary to discharge in some way, lest God's sacred name should be exposed to ridicule. This estimation God left to the arbitration of the priest. But if an animal might be offered in sacrifice, no redemption was allowed; and if any one had substituted another animal, or paid the price of it, he was punished for his fraud, for both (i.e., the animal, and its substitute or price) were consecrated to God. The estimation, which is imposed upon one who had vowed, is irreversible, since God simply commands the Israelites to stand by the judgment of the priest, and to abide by the taxation, as it is called, enjoined upon them as a fixed rule; and, besides, they were to add a fifth part, as an additional fine, to the price appointed by the priest.

Any unclean beast - See on Leviticus 27:2 (note).

And if it be any unclean beast, of which they do not offer a sacrifice unto the Lord,.... Any creature, excepting a dog, the price of which was not to be brought into the house of the Lord; besides oxen, sheep, goats, rams, and lambs; though some understand it even of such that have blemishes on them, and so not fit to be offered unto the Lord; so Jarchi and others (x):
then he shall present the beast before the priest; to be viewed, examined, and judged of as to its worth, and a value put upon it, that it might be sold or redeemed, as no other but a beast might; so it is observed birds, wood, frankincense, and ministering vessels, have no redemption, for it is only said a beast (y).
(x) Maimon. & Bartenora in Misn. Menachot, c. 12. sect. 1. (y) Misn. ib.

Every unclean beast, however, - an ass for example, - which could not be offered in sacrifice, was to be placed before the priest for him to value it "between good and bad," i.e., neither very high as if it were good, nor very low as if it were bad, but at a medium price; and it was to be according to this valuation, i.e., to be worth the value placed upon it (הכּהן כּערכּך according to thy, the priest's, valuation), namely, when sold for the good of the sanctuary and its servants.

Unclean - Either for the kind, or for the quality of it; if it were such an one as might not be offered.