Leviticus 27:26

Overview - Leviticus 27
He that makes a singular vow must be the Lord's.
The estimation of the person;
of a beast given by vow;
14 of a house;
16 of a field, and the redemption thereof.
28 No devoted thing may be redeemed.
30 The tithe may not be changed.
Treasury of Scripture Knowledge

Leviticus 27:26  (King James Version)
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.
 


the firstling
Hebrew first born, etc.
As these firstlings were the Lord's before, it would have been a solemn mockery to pretend to make them a matter of a singular vow; for they were already appointed, if clean, to be sacrificed.

which
Exodus 13:2 Exodus 13:12 Exodus 13:13 ; 22:30 Numbers 18:17 ; Deuteronomy 15:19