Leviticus 27:8-10

Good News Translation

⁸ If any of you make a vow and are too poor to pay the standard price, you shall bring the person to the priest, and the priest will set a lower price, according to your ability to pay.

⁹ If your vow concerns an animal that is acceptable as an offering to the Lord, then every gift made to the Lord is sacred, ¹⁰ and you may not substitute another animal for it. If you do, both animals belong to the Lord.