No man shall sanctify it, to wit, by vow; because it is not his own, but the Lord's already, and therefore to vow such a thing to God is a tacit derogation from and a usurpation of the Lord's right, and a mocking of God by pretending to give him what we cannot withhold from him. Ox or sheep: under these two eminent kinds he comprehends all other beasts which might be sacrificed to God, the firstlings whereof could not be redeemed, but were to be sacrificed; whereas the firstlings of men were to be redeemed, and therefore were capable of being vowed, as we see 1 Samuel 1:11.
Related Commentaries of Leviticus 27:26
Leviticus 27:26
26 Only the firstling of the beasts, which should be the LORD'S firstling, no man shall sanctify it; whether it be ox, or sheep: it is the LORD'S.