He: this refers to the person who made the promise to God.

Substitute … exchange: these two verbs have very similar meanings but may be slightly different. According to some writers substitute gives the idea of replacing one animal by an exact equivalent, while exchange is to replace with something different. But the Septuagint translated the two by a single term. And they may be translated by a single verb in the receptor language, if synonyms cannot be found, or if it would be unnatural to use two verbs here.

A good for a bad, or a bad for a good: this information is left implicit in Good News Translation, but it emphasizes that substitutes are forbidden under all circumstances—even when the worshiper wants to provide a better animal than originally presented. In some languages this may be stated as follows “even if a better animal is presented.”

Be holy: dynamically rendered “belong to the LORD” in this context.

Quoted with permission from Péter-Contesse, René and Ellington, John. A Handbook on Leviticus. (UBS Helps for Translators). New York: UBS, 1990. For this and other handbooks for translators see here .