Numbers 18:8-19

Then the  Lord spoke to Aaron, “Behold, a I have given you charge of the contributions made to me, all the consecrated things of the people of Israel. I have given them to you b as a portion and to your sons as a perpetual due. This shall be yours of the most holy things, reserved from the fire: every offering of theirs, every grain offering of theirs and every c sin offering of theirs and every d guilt offering of theirs, which they render to me, shall be most holy to you and to your sons. 10 In a most holy place shall you eat it. Every male may eat it; it is holy to you. 11 This also is yours: the contribution of their gift, all the e wave offerings of the people of Israel. I have given them to f you, and to your sons and daughters with you, as a perpetual due. g Everyone who is clean in your house may eat it. 12  h All the best of the oil and all the best of the wine and of the grain i the firstfruits of what they give to the  Lord, I give to you. 13 The first ripe fruits of all that is in their land, j which they bring to the  Lord, shall be yours. k Everyone who is clean in your house may eat it. 14  l Every devoted thing in Israel shall be yours. 15  m Everything that opens the womb of all flesh, whether man or beast, which they offer to the  Lord, shall be yours. Nevertheless, n the firstborn of man you shall redeem, and the firstborn of unclean animals you shall redeem. 16 And their redemption price o (at a month old you shall redeem them) you shall fix at five shekels
A  shekel was about 2/5 ounce or 11 grams
in silver, according to the shekel of the sanctuary, q which is twenty gerahs.
17  r But the firstborn of a cow, or the firstborn of a sheep, or the firstborn of a goat, you shall not redeem; they are holy. You shall sprinkle their blood on the altar and shall burn their fat as a food offering, with a pleasing aroma to the  Lord. 18 But their flesh shall be yours, as s the breast that is waved and as the right thigh are yours. 19  t All the holy contributions that the people of Israel present to the  Lord I give to you, and to your sons and daughters with you, as a perpetual due. u It is a covenant of salt forever before the  Lord for you and for your offspring with you.”
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