Leviticus 27:10

He shall not alter it, nor change it, a good for a bad, etc. - Whatever was consecrated to God by a vow, or purpose of heart, was considered from that moment as the Lord's property; to change which was impiety; to withhold it, sacrilege. Reader, hast thou ever dedicated thyself, or any part of thy property, to the service of thy Maker? If so, hast thou paid thy vows? Or hast thou altered thy purpose, or changed thy offering? Has he received from thy hands a bad for a good? Wast thou not vowed and consecrated to God in thy baptism? Are his vows still upon thee? Hast thou "renounced the devil and all his works, the pomps and vanities of this wicked world, and all the sinful lusts of the flesh?" Dost thou feel thyself bound "to keep God's holy will and commandments, and walk in the same all the days of thy life?" Was not this thy baptismal covenant? And hast thou renounced It? Take heed! God is not mocked: that which thou sowest, thou shalt also reap. If thou rob God of thy heart, he will deprive thee of his heaven.

27:10 He shall not alter it, nor change it - Two words expressing the same thing more emphatically, that is, he shall in no wise change it, neither for one of the same, nor of another kind: partly because God would preserve the reverence of consecrated things, and therefore would not have them alienated, and partly to prevent abuses of them who on this pretence might exchange it for the worse. It and the exchange - That is, both the thing first vowed, and the thing offered or given in exchange. This was inflicted upon him as a just penalty for his levity in such weighty matters.