Throughout Leviticus so far, and certainly prior to that in the back half of Exodus in the instructions on how the tabernacle was to be built. we’ve seen Yahweh be very specific about how His people were to interact with Him in worship. He cares where they do it, how they do it, who is doing it, what they are wearing, their purity, the purity of the altars, the process, etc. The point is, it is understandable that His people would not immediately know how to properly interact with a holy God so God has made it very clear to them how it is to be done. Perhaps unsurprisingly, it doesn’t take long for those instructions to be subverted, and the consequences are severe.
The chapter continues on what is the very first day of Aaron being the official high priest having just completed the week long sanctification and sacrificing process. Two of his sons, Nadab and Abihu, who have also gone the ordination process, each pick up a censer, put fire in it, then add incense. At a brief glance, these actions are not completely foreign, as ordained priests we should assume they had the right to offer incense. But the narrative takes a drastic turn, for what they are offering is “unauthorized” or “strange” fire.
What does that mean exactly, strange fire? There are a few options. Incense was made by mixing spices together and the vaporizing them by putting them in a censer containing glowing lumps of coal. It’s possible that strange fire is a description of any one of those items coming from unclean sources (coals that come from somewhere from the altar, a mix of spices that wasn’t allowed, wrong time of day for the daily incense offering, etc.) However, the core of the issue is that it was a fire which God had not commanded them. It has been very clear that that God’s priests are to obey the law promptly and exactly. Certainly, Aaron’s sons know better than to freelance. And yet, here they are.
God’s reaction is swift and fierce. Fire comes from the Lord, in much the same way as it did to consume what had been offered to him in the previous chapter, and the two fellas die in the judgment of God. Moses quickly declares what was at stake, a basic summary being that the closer a man is to God, the more attention he must pay to the holiness of God. This principle is not restricted to just the priests, we find it similarly occurring to God’s people as a whole. As God’s chosen people, similarly to God’s chosen personal servants, there is a higher expectation upon them as mediators and representatives. In the book of Amos, the nations that surround Israel are condemned for all of the heinous things that they have done to people and other nations. Israel and Judah, however, are also condemned but not for those same things but simply for not keeping the Law of God (which from a human perspective we can recognize may not always have the same worldly consequences but are of the utmost consequence in their right relationship with God).
Broadly, how we feel about this instant judgment upon these two fellas tends to reveal our understanding/reverence of the holiness of God. If we believe it is a passive thing or casual thing, the judgment seems harsh. But if we recognize what a holy thing God’s worship is, the punishment is not offensive at all.
Aaron, certainly upset but also understanding what has just occurred, holds his peace. Moses has what remains of Nadab and Abihu buried outside the tabernacle area. He also instructs Aaron and his remaining two sons that they may not do some of the standard mourning actions in response to their death (letting down hair, tearing clothes, etc.) We should probably see this as an instruction to act with consistency of God’s perspective as this was a just response to the actions of the Nadab and Abihu. However, the rest of the people can “bewail” or mourn/remember them, lest they forget the situation and bring risk upon themselves in the future.
Then the Lord speaks to Aaron directly, the only time this will happen in Leviticus (most of the time Moses is acting as an intermediary). God instructs Aaron that they should not be drinking any booze when they enter the tent of meeting (makes sense, ya’ll shouldn’t be drinking before you head to work either). Reasonably, we might ask why this is coming up now. It’s possible alcohol might have contributed to the actions of the two boys of Aaron, recently deceased. It’s also possible that God is heading off actions Aaron and his remaining sons might take in reaction to the death of the fellas, drinking to cheer themselves up. Whether it’s one of these of another reason, God’s warning is a reminder that they are serving in a high calling and must lead in these areas. They are to distinguish between what is holy and common, clean and unclean. As teachers, they must first be faithful followers. (This word from God was certainly good news for Aaron, who is being assured by direct contact from God that he is to remain in the office of high priest doing the work of the Lord, despite the actions of his sons).
Then Moses reminds them that the work must continue and that there are sacrifices still available that they are to eat. Specifically, the goat that was to be offered in the purification offering (chapter 9) had portions that were to be eaten by the priests as long as the blood of the sacrifice wasn’t brought into the tent of meeting. It wasn’t, so they should have eaten it. in a day where lack of following the guidelines has already been disastrous, Moses is incensed.
Aaron basically explains that, based upon what has happened already today, he didn’t want to take any chances and get this wrong. He and his remaining sons had been eye witnesses to making a mistake with the holy things, so they were going to take what they considered the safest option and not risk unintentionally eating something that belonged to the Lord alone. Both of these thoughts are reasonable, really. This is their first day, after all, seems like a sizable risk to maybe get the distinctions wrong. Further, the consequences were significant, they would rather be overly cautious.
This explanation is sufficient for Moses, who was likely glad to hear Aaron and the boys are looking at God’s worship with the right sense of reverence.