Charles Ellicott Commentary Leviticus 27:26

"Only the firstling among beasts, which is made a firstling to Jehovah, no man shall sanctify it; whether it be ox or sheep, it is Jehovah`s." — Leviticus 27:26 (ASV)

Only the firstling of the beasts.—A better rendering is nevertheless the firstlings, and so on, as this rendering also suits Leviticus 27:28, which begins with the same particle and is translated in the Authorized Version, “notwithstanding.”

Having laid down the regulations about the four classes of objects that may be vowed to the Lord—namely, concerning:

1. persons (Leviticus 27:2–8);
2. animals (Leviticus 27:9–13);
3. houses (Leviticus 27:14–15);
4. lands (Leviticus 27:16–25).

—the legislator concludes by pointing out two exceptions to the rules about votive offerings previously discussed. The two classes of objects that are forbidden to be vowed are:

1. the firstlings of beasts;
2. devoted things.

The firstlings already belonged to the Lord by an express statute (Exodus 13:2). To vow, therefore, to the Lord that which was His own is a mockery.

Which should be the Lord’s firstling.—Rather, which is born as a firstling to the Lord, that is, one which, by virtue of its being a firstling and by its very birth, is the property of the Lord.