He shall not alter it nor change it
Some think these two words signify the same, but Abarbinel F19 makes them different; according to him, to "alter" is for one of another kind, as one of the herd for one of the flock, or the contrary; and to "change" for one of the same kind:
a good for a bad, or a bad for a good;
or, as the Targum of Jonathan,
``that which is perfect for that which has a blemish in it, or what has a blemish in it for that which is perfect;''a change might not be made neither for the better nor for the worse, but the creature devoted was to be taken as it was; if not fit for sacrifice it was to be sold, and its price put to other uses; for, as Abarbinel F20 observes, whatsoever was devoted to sacred use was never to be put to any profane one; and this was also to teach men not to be hasty and fickle in such things, but to consider well what they did, and abide by it; for if such alterations and changes could be admitted of, a man after he had vowed might through covetousness repent, and bring a bad one instead of a good one, or, under pretence of bringing a good one instead of a bad one, might bring a bad one and say it was good, as Bechai F21 observes; even one worse than he had brought, thinking to impose upon the ignorance of the priest; and indeed if he was sincere in it, and had a mind to bring a better than what he had vowed, it was not allowed of; if he made any change, though it was for the better, he was to be beaten, as Maimonides F23 affirms:
and if he shall at all change beast for beast;
whether of the same or of a different kind, or whether for better or worse:
then it and the exchange thereof shall be holy:
both of them were to be the Lord's, and appropriated to sacred use, of one sort or another, either for sacrifice or for the priests family, or the price of it for the repairs of the sanctuary.
F19 Apud Muis. in loc.
F21 Apud Muis. ib.
F23 Hilchot Temurah, c. 1. sect. 1.