Numbers 18:9

18:9 Of all the most holy offerings reserved ¹  from the fire this will be yours: Every offering of theirs, whether from every grain offering or from every purification offering or from every reparation offering which they bring to me, will be most holy for you and for your sons.

Numbers 19:20

19:20 But the man who is unclean and does not purify himself, that person must be cut off from among the community, because he has polluted the sanctuary of the Lord; the water of purification was not sprinkled on him, so he is unclean.

[18:9]  ¹ tn Heb “from the fire.” It probably refers to those parts that were not burned.