John Calvin on Numbers 18:15-19

15. Every thing that openeth the matrix. The same thing is now ordained as to the first-born, viz., that the priests should have them also for themselves; though at the same time a distinction is inserted, that the first-born of man should be redeemed. With regard to unclean beasts, the owners were free either to redeem or to kill them. But, since this matter is not professedly treated of here, God only briefly declares that He gives to the priests whatever profit may be made of the first-born. The command that the first-born should be redeemed according to the estimation of the priests, does not mean that the priests should themselves prescribe the value, as if they had the authority to do so; but that estimation is referred to by which they were bound according to God’s command, as we saw elsewhere; and this may be readily gathered from the context, because the price is presently added, which God Himself had fixed. As to the first-born of clean animals, another law is given, viz., that they should be killed at the altar, and their fat burned, whilst the flesh was to belong to the priests, like the breast and the right shoulder of the burnt-offerings. But, lest any of the Levites or of the people — since men are always eager for innovation — should ever attempt to violate this decree, all controversy is removed in future ages, when God declares that what He gave to the priests He would never have taken away from them. First, He uses the word edict or decree, חק from חקק describere, decernere, statuere. — Taylor’s Concordance. which others translate “statute:” and then adds the title “covenant,” Addition Fr. “voire, Paction de sel." in order that its observation may be more sacred, and less exposed to contentions and quarrels; for nothing could be more indecent than that the priests should dispute regarding their rights and privileges. God, then, signifies that He shall be Himself outraged, if any one should trouble the priests. By the word “salt,” perpetuity is metaphorically expressed; in which, however, God appears to allude to the sacrifices, which it was not lawful to offer unless seasoned with salt; that the Israelites might learn that, by earthly and corruptible things, something greater was designated; for we know that salted meats do not so easily become corrupt. In a word, this metaphor implies inviolable stability.

Leviticus 6

Leviticus 6:16-18, 26-29

16. And the remainder thereof shall Aaron and his sons eat: with unleavened bread shall it be eaten in the holy place; in the court of the tabernacle of the congregation they shall eat it.

16. Quod superfuerit ex minha, comedent Aharon et filii ejus: azymum comedetur in loco sancto, in atrio tabernaculi conventionis, comedent illud.

17. It shall not be baken with leaven. I have given it unto them for their portion of my offerings made by fire; it is most holy, as is the sin offering, and as the trespass offering.

17. Non coquetur fermentatum: portionem eorum dedi illud ex oblationibus meis ignitis: sanctitas sanctitatum est, sicut oblatio pro peccato, et sicut oblatio pro delicto.

18. All the males among the children of Aaron shall eat of it. It shall be a statute for ever in your generations concerning the offerings of the LORD made by fire: every one that toucheth them shall be holy.

18. Omnis masculus in filiis Aharon comedet illud, statutum perpetuum est satatibus vestris de oblationibus ignitis jehovae: qui tetigerit eas sanctificabitur.

26. The priest that offereth it for sin shall eat it: in the holy place shall it be eaten, in the court of the tabernacle of the congregation.

26. Sacerdos oblationem pro peccato comedet, in loco sancto comedetur, in atrio tabernaculi conventionis.

27. Whatsoever shall touch the flesh thereof shall be holy: and when there is sprinkled of the blood thereof upon any garment, thou shalt wash that whereon it was sprinkled in the holy place.

27. Qui tetigerit carnem ejus sanetificabitur, et si defluxerit de sanguine ejus super vestera, illud super quod defiuxerit lavabis in loco sancto.

28. But the earthen vessel wherein it is sodden shall be broken: and if it be sodden in a brazen pot, it shall be both scoured, and rinsed in water.

28. Et vas testaceum in quo coquetur, confringetur: quod si in vase aeneo cotta fuerit, defricabitur et lavabitur aqua.

29. All the males among the priests shall eat thereof: it is most holy.

29. Omnis masculus in sacerdotibus comedet illam: sanctitas sanctitatum est.