Leviticus 10:14
And the wave breast and heave shoulder shall ye eat in a clean place; thou, and thy sons, and thy daughters with thee: for they be thy due, and thy sons’ due, which are given out of the sacrifices of peace offerings of the children of Israel.
The wave breast and heave shoulder from the peace offerings of Israel were assigned as a due to the priests, to be eaten in a clean place by them with their sons and daughters with them, as part of the laws governing Israel's offerings and the priests' duties in sanctuary worship. The eating of meat under this provision was very limited and lean, for the wave breast and heave shoulder were a lean portion from peace and wave offerings, which were not always flesh but sometimes corn, wine, or wheat. The priests had no part of the whole burnt offerings and ate no meat of any beast whose blood was carried into the sanctuary, so the amount they ate was small.
The provision gives no license for eating fat, diseased, or unclean meat, for all the fat of those animal offerings was taken away and burned to the Lord and the people were positively forbidden to eat fat. The lean meat allowed was only from young, healthy animals without blemish, confirming that diseased and fat meat, and swine's flesh swimming in grease, are unwholesome and unfitted for feeble men and women of this age. The verse belongs among the passages describing the yearly services of the Levitical sanctuary, whose service typified Christ's priestly ministry in the heavenly sanctuary. In cases where sacrificial flesh was eaten by a priest, the priest bore the transgressor's iniquity in his own person, and the sin was thus borne into the sanctuary awaiting the day of atonement.
In its chapter setting, Nadab and Abihu treated the use of strange fire as though it made no difference and went utterly contrary to the clear and explicit command to use sacred fire in burning incense. They offered strange fire and incense kindled with common fire before Jehovah which He had not commanded them, putting no difference between what God had sanctified and what He had not, and fire coming forth from before Jehovah devoured them so they died before Him. The contrast between Leviticus 9 and Leviticus 10 shows that God's wrath is founded in eternal justice and is always against sin, executed against persons only when they have identified themselves with sin. In Leviticus 9 the offerings represented sin from which the people had separated, and fire coming forth to consume the burnt offering and the fat was blessed evidence that God consumed the sin and they stood forgiven, free and clear, while in Leviticus 10 Aaron's sons were destroyed because they identified themselves with sin and broke God's express commandments.
The chapter teaches the difference between the holy and the common and the necessity of temperance, showing that God's servants must be clear-headed, temperate men, since Aaron's sons had their minds confused by the wine they drank, and God is as particular now as then. A substitute for what God has commanded is not acceptable, for sacred things are not to be treated as common. To disregard what God has plainly said and do in its stead what He has not commanded because it is the custom, while still hoping to be accepted in His sight, is to follow their example and cannot hope to live. The record of ancient Israel stands for instruction and admonition to those with the light of Israel's experience, fulfilled prophecy, and the final warning against corruption of God's word, upon whom the ends of the world are come, that they learn its lesson, take heed lest they fall, and escape imminent danger.
Failing to distinguish holy from profane makes disobedience a light thing and leads to hiding the eyes from His Sabbaths, while distinguishing holy from profane leads to obeying God and hallowing His Sabbaths. The chapter thus proves God has the right to specify how He is worshiped, so since God for a wise reason sanctified and claimed the seventh day, it makes a difference what day is offered to the Lord, and God is as jealous of His word now as then.