1 And the Lord spake unto Moses after the death of the two sons of Aaron, when they offered before the Lord, and died;

2 And the Lord said unto Moses, Speak unto Aaron thy brother, that he come not at all times into the holy place within the veil before the mercy seat, which is upon the ark; that he die not: for I will appear in the cloud upon the mercy seat.

The opening of this chapter references back to the priestly disobedience of Aaron’s two sons, Nadab and Abihu, who were consumed in fire by the Lord for their sin. This memory is invoked to remind Aaron of the strictness of his calling, particularly in matters of “the holy place,” which is the inner chamber of the tabernacle where the Ark of the Covenant resides. Aaron is informed, on pain of death, that he must never come into that place outside of the very specific conditions that God will describe in the rest of this chapter. And none of the other priests could ever venture into that place. Only the High Priest, and only once a year, as we will soon read.

The reason is given in verse 2. The Lord, Himself, will dwell in a cloud upon the mercy seat, which is the lid of the Ark of the Covenant. His presence and His glory are wonderful and terrible, consuming like a flame any who are not prepared beforehand.

There is in these verses an example of the principle of leadership. With leadership responsibility there comes great obligation, great consequence for failure, and also great privilege. Aaron will officiate as the highest authority in bearing the sins of the people, he is given the instructions of how to do so under pain of death, and he will be the only one allowed into the very chambers of the Lord. Obligation, consequence, and privilege.