Leviticus 27:9-13 - Redemption Of Vowed Animals
9 And if it be a beast whereof men may bring near an oblation unto Yahweh, all that whereof aught is given to Yahweh, shall be holy. 10 He shall not alter it, nor change it - good for bad or bad for good, - but if he, do, change beast for beast, then shall, both it and what was given in exchange for it be holy.
11 And, if it be any unclean beast whereof men may not bring near an oblation to Yahweh, then shall he present the beast before the priest: 12 and the priest shall estimate it, whether it is good or bad, - according to thine estimate, O priest, so, shall it be. 13 But if he should please to redeem, it, then shall he add the fifth part thereof unto thine estimate.