“and offered strange fire before Yahweh.” It is not clear what sin Nadab and Abihu had committed. Many scholars postulate that it was because they did not take the fire that God had ignited on the great bronze altar, but that is not clearly commanded in Scripture except for the High Priest on the Day of Atonement. So, while that could have been the sin they committed, there is no way to prove that from Scripture. The Old Testament commentary by Keil and Delitzsch says, “This might be called ‘strange fire’ if it was not offered in the manner prescribed in the law, just as in Exod. 30:9 incense not prepared according to the direction of God is called ‘strange incense.’” One thing we can be sure of is that God could have told us exactly what the sin of Nadab and Abihu was, and the fact that He did not tells us that He wants us to focus on the importance of obedience, not get distracted by analyzing the sin the men committed.
There is no explanation in the text for this action of Aaron’s sons. God’s way is to be explicit about how He wanted things to be done in a way that pleased Him, so it seems that, even though we do not know the exact sin, we can see that the motive for the men’s actions could only be pride and arrogance, not a simple mistake. The fact that Aaron was silent about the death of his sons (Lev. 10:3) shows that he understood that his two sons had sinned against Yahweh in an egregious manner. If they simply had made a mistake, surely Aaron would have said something about it, and both he and Moses made mistakes in trying to lead Israel.
There are a number of important lessons that we can learn from this incident. One is that God has told us how to do things in a way that pleases Him, and it is important to love God enough, and be humble enough, to do things God’s way. To ignore God’s way of doing things and go our own way and make up our own rules is dangerous. For example, today people get saved by taking Christ as Lord and believing God raised him from the dead (Rom. 10:9). There are many people who ignore that and say, “I am a good person; I believe God will save me.” But that belief is deadly because none of us are “good enough” to be saved. We all need a Savior from sin.
Another lesson in this record is that to whom much is given, much will be required. Nadab and Abihu were the very first generation of priests, and Nadab was in line to become the High Priest (Exod. 6:23). They had a lot of responsibility and influence. Their example of ignoring God’s commands and doing things their own way would almost certainly have been very harmful to Israel, especially in this first couple of years after leaving Egypt. Furthermore, how would Nadab act after he became the High Priest? The fact that he was serving as a priest meant he was at least 30 years old, and it seems that at his age his attitude toward the things of God would not have changed much or even changed for the worse if he was given the position of High Priest, which had even more power and responsibility than he already had. It is a general principle that people in the believer community who have lots of responsibility are held to a higher standard than the average believer, and every leader needs to be aware of that (James 3:1).