Vayikra 27:8-10

Orthodox Jewish Bible

⁸ But if he be poorer than thy evaluation, then he shall present himself before the kohen, and the kohen shall value him; according to the ability of the one who vowed the neder shall the kohen value him.

⁹ And if it be a behemah, whereof men bring a korban unto Hashem, all that any man giveth of such unto Hashem shall be kodesh.

¹⁰ He shall not exchange it, nor substitute it, a tov for a rah, or rah for tov: and if he shall at all substitute behemah for behemah, then it and the substitute thereof shall be kodesh.