Today’s chronological Old Testament reading from Leviticus 10 is undoubtedly the best known part of Leviticus for those of us who grew up "in the church." The story of Nadab and Abihu was as large part of why I saw myself as different from members of other “Christian” groups. (And why I felt the need to use quotation marks when using the word “Christian” in that context). Nadab and Abihu offered the unauthorized sacrifice of “strange fire” before God, and they were destroyed... just as Noah would have been destroyed if he would have used any other wood than gopher word. Our church offered only authorized worship to God— we sang without musical accompaniment, baptized only by immersion “for the remission of sins,” and observed communion every first day of the week. Any deviation from that (and other forms and formats) would be the strange fire that burned Nadab and Abihu to a crisp. (Of course, the church down the street condemned us for introducing the strange fire of Christian camps, orphans homes and eating in the church building, but that is just silly).
(See this older post, which I had forgotten about, for a similar discussion.)
One problem with our rather narrow use of this story of Aaron's oldest sons is that we read the story and fail to read the whole context. In Leviticus 8-9, Aaron and his sons were ordained as priests. Very meticulous and somewhat strange (see 8:22-29) instructions were given for the ordination process, and these instructions were carried out to the letter. In chapter 9, Aaron begins his priestly ministry, and the first time he carried out a burnt offering, sin offering and fellowship offering as high priest, the ritual is interrupted (or rather completed) by fire coming from presence of God to consume the sacrifice (Lev. 9:23-24). That wasn’t normally part of the sacrificial procedure, and it must have been impressive. But evidently it was not impressive enough.
The tenure of Nadab and Abihu as priests wasn't very long— about two verses (Lev. 10:1-2). The text says that they offered “unauthorized fire” (NIV) or “strange fire” (NET) before the Lord. The word here is the same word for "stranger" or "foreigner" (see Deut 25:5, 32:16, etc.). A similar expression occurs in Exodus 30:9 when it condemns “other incense” ("other" is the same word as "unauthorized"). In Numbers 6, the command is given to keep the fire on the altar burning perpetually (6:12-13), but here Nadab and Abihu bring the fire for the sacrifice in their censers from some other place. Remember, the last fire on the altar had fallen from God himself, so did they get busy or distracted and allow that fire to go out and then try to cover their sin by introducing “strange fire?”
Or did they get drunk? Immediately following the death of Nadab and Abihu, instruction is given that priests are not to drink before serving as priests (Lev. 10:9-11). Is that a coincidence? Or does it seem probable that alcohol had clouded Nadab and Abihu’s judgment and led them to fail to "distinguish between the holy and the common." (Lev 10:10). Whatever the case, one would think that Aaron, Eleazar and Ithamar (Aaron’s remaining sons and replacement priests) would have been very careful about sacrifice procedure from that point on.
Or maybe not? At this point, the story gets even more interesting. Aaron and the two replacement priests were told not to mourn publically but to continue their duties as priests. When Moses checks up on them, he discovers they have not eaten their portion of the sin offering in the Tabernacle as they were required to do. Remember what happened to Nadab and Abihu when they free-lanced with the sacrificial procedure? Well, Moses comes charging in screaming, “What are you doing?” (a rather loose translation of Lev 10:17-18). Aaron replies (with a lump in his throat, we can imagine), “Today they sacrificed their sin offering and their burnt offering before the LORD, but such things as this have happened to me. Would the LORD have been pleased if I had eaten the sin offering today?” (Lev 10:19, NLT).
Aaron and his sons had not publicly mourned the death of Nadab and Abihu as they had been commanded. They had gone on with their priestly duties as they had been commanded. But they could not bring themselves to eat after witnessing their sons/brothers dying in such a horrible way. They weren't rebelling against God’s commands. It was just that human weakness and frailty would not allow them to eat. Moses was satisfied with that explanation. The absence of fire falling from sky indicates that God recognized the difference as well.
The story of Nadab and Abihu makes it very clear that it is not small thing to ignore what God has commanded and authorized. They story of Eleazar and Ithamar makes it very clear that God sees human weakness and frailty differently than willful disregard. These stories also make it clear that it is God and only God who decides between these two types of failures and whether or not the fire will fall from His presence. We would do well to take seriously both sides of this story.