Exodus 29:33-35

New Revised Standard Version, Anglicised Catholic Edition

³³ They themselves shall eat the food by which atonement is made, to ordain and consecrate them, but no one else shall eat of them, because they are holy. ³⁴ If any of the flesh for the ordination, or of the bread, remains until the morning, then you shall burn the remainder with fire; it shall not be eaten, because it is holy.

³⁵ Thus you shall do to Aaron and to his sons, just as I have commanded you; over seven days you shall ordain them.