26 But a man may not give by oath to the Lord the first-fruits of cattle which are offered to the Lord: if it is an ox or a sheep it is the Lord's. 27 And if it is an unclean beast, then the owner of it may give money to get it back, in agreement with the value fixed by you, by giving a fifth more; or if it is not taken back, let it be given for money in agreement with your valuing. 28 But nothing which a man has given completely to the Lord, out of all his property, of man or beast, or of the land which is his heritage, may be given away or got back in exchange for money; anything completely given is most holy to the Lord. 29 Any man given completely to the Lord may not be got back: he is certainly to be put to death. 30 And every tenth part of the land, of the seed planted, or of the fruit of trees, is holy to the Lord. 31 And if a man has a desire to get back any of the tenth part which he has given, let him give a fifth more. 32 And a tenth part of the herd and of the flock, whatever goes under the rod of the valuer, will be holy to the Lord. 33 He may not make search to see if it is good or bad, or make any changes in it; and if he makes exchange of it for another, the two will be holy; he will not get them back again.

Matthew Henry's Commentary on Leviticus 27:26-33

Commentary on Leviticus 27:26-33

(Read Leviticus 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.