Bible: Num 18:15-17

18:15 The firstborn of every womb which they present to the Lord, whether human or animal, will be yours. Nevertheless, the firstborn sons you must redeem, 1  and the firstborn males of unclean animals you must redeem. 18:16 And those that must be redeemed you are to redeem when they are a month old, according to your estimation, for five shekels of silver according to the sanctuary shekel (which is twenty gerahs). 18:17 But you must not redeem the firstborn of a cow or a sheep or a goat; they are holy. You must splash 2  their blood on the altar and burn their fat for an offering made by fire for a pleasing aroma to the Lord.
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