(27) And if it be of an unclean beast.--That is, if he vows the firstling of an unclean beast he could redeem it according to the valuation of the priest with the addition of one-fifth over and above the fixed value. If he did not redeem it the treasurer of the sanctuary sold it to anyone who liked to buy it at this valuation, and the proceeds were devoted to the maintenance and repairs of the sanctuary. As this is at variance with the law laid down in Exodus 13:13; Exodus 34:20, where it is enacted that the firstborn of an ass is either to be redeemed with a sheep, or is to be put to death, the authorities during the second Temple interpreted the precept in the passage before us as not applying to the firstborn of the unclean animals, but to unclean animals generally which are dedicated for the repairs of the sanctuary.

27:26-33 Things or persons devoted, are distinguished from things or persons that were only sanctified. Devoted things were most holy to the Lord, and could neither be taken back nor applied to other purposes. Whatever productions they had the benefit, God must be honoured with the tenth of, if it could be applied. Thus they acknowledge God to be the Owner of their land, the Giver of its fruits, and themselves to be his tenants, and dependants upon him. Thus they gave him thanks for the plenty they enjoyed, and besought his favour in the continuance of it. We are taught to honour the Lord with our substance.And if it be of an unclean beast,.... This is to be understood, not of the firstling of unclean creatures in common, which were to be redeemed with a lamb, and not with money, according to the estimation of the priest, and a fifth part added to that; but of such as were sanctified, or vowed, for the reparation of the sanctuary, as Jarchi notes:

then he shall redeem it according to thine estimation; the price the priest should set upon it, how much it was worth in his judgment:

and shall add a fifth part of it thereto; to the price, set upon a fifth part of that over and above the sum; this the sanctifier, or he that made the vow, was obliged to pay, if he thought fit to redeem it:

or if it be not redeemed; by him, he does not choose to give the price, and the fifth part:

then it shall be sold according to thy estimation; to another man, without the fifth part, that chooses to purchase it, and then the purchase money was laid out for sacred uses.