As someone who pays a close deal of attention to the behavior of the priests and Levites in scripture  and in our contemporary world as believers, there are some stories that fill me with a great deal of personal caution and concern. One of those stories occurs right at the beginning of the priestly service of Nadab and Abihu, the two oldest sons of Aaron. Before talking about this story itself directly and my own concerns about it as it relates to my own life and service, I would like to provide a little bit of context first. We first meet Nadab and Abihu as bit characters in an important dinner invitation that God gave to Moses and the priestly and civil leadership of Israel at the beginning of their sojourn in Mt. Sinai, which we find in Exodus 24:1-2, 9-12: “Now He said to Moses, “Come up to the Eternal, you and Aaron, Nadab and Abihu, and seventy of the elders of Israel, and worship from afar. And Moses alone shall come near the Eternal, but they shall not come near, now shall the people go up with him.” “Then Moses went up, also Aaron, Nadab, and Abihu, and seventy of the elders of Israel, and they saw the God of Israel. And there was under His feet as it were a paved work of sapphire stone, and it was like the very heavens in its clarity. But on the nobles of the children of Israel He did not lay His hand. So they saw God, and they ate and drank. Then the Eternal said to Moses, “Come up to me on the mountain and be there; and I will give you tablets of stone, and the law and commandments which I have written, that you may teach them.””
Considering that up to only a few weeks ago Nadab and Abihu had been slaves, the change from slavery to being part of a priestly elite must have been very heady for these young men. Perhaps some of their pride of increased station went to their head. Perhaps they thought that they were something special themselves for having been called by God by name to such an elite soiree with Him to eat and drink and enjoy some time. Such things are not stated directly in scripture, but they are easy to imagine, especially since the two younger sons of Aaron, Eleazar and Ithamar, are not mentioned as having been invited to this party. Knowing how brothers tend to be from my own experience, the matter of receiving invitations or not receiving invitations can be the source of some tension between siblings. For whatever reason, though, Nadab and Abihu, though they were given a special and important calling by God, did not properly respect that calling.
We see this in their tragic end in Leviticus 10:1-3, which takes place shortly after the beginning of the priestly ministry, showing it did not take long for their conduct to catch up with them: “Then Nadab and Abihu, the sons of Aaron, each took his censer and put fire in it, put incense on it, and offered profane fire before the Eternal, which He had not commanded them. So fire went out from the Eternal and devoured them, and they died before the Eternal. And Moses said to Aaron, “This is what the Eternal spoke, saying: ‘By those who come near Me I must be regarded as holy; and before all the people I must be glorified.’ ” So Aaron held his peace.” Here we see that the standards of service to God are very high ones. God holds those who serve His people accountable for showing an example of holiness and honor, and that is a standard that we as fallible and flawed human beings often struggle with. The reason why this standard is held so high is because the failures of leadership to properly serve God and present an example of holiness leads people to blaspheme God for His lack of holy standards and His lack of enforcement of those standards. Those of us who serve or lead, therefore, have a tough standard to adhere to.
I ponder these matters somewhat often with regards to my own life. After all, given that I am a person who has been given certain fairly obvious talents and gifts by God, and also since I am a person with a compulsion to serve God and others with those talents and abilities that I have been given, the subject of whether my service brings benefit to others and glory to God is something that I think about somewhat often. I am aware of my flaws and weaknesses and shortcomings, most of which are sufficiently obvious to draw attention from others as well, and often with regards to my service I reflect upon the variety of motives and goals I have in such matters, knowing that such matters are often very complicated. Knowing the burden I carry as a result of my own life, I strive with some difficulty to avoid spreading that suffering to others, while seeking after the deep longings of my heart with some concern and anxiety over whether they will ever be satisfied.
I would hope that I do not face the same fate as Nadab and Abihu for their strange fire. I would hope that such modest service as I am able to provide brings others joy and encouragement, rather than fear and anxiety. I would hope that the struggles I face do not cause others to stumble or to question God or others as to their failures of setting and enforcing proper boundaries in conversation and conduct. I would hope that the presence or absence of invitations and other social courtesies that I tend to notice rather strongly do not hinder my own service or my own fond feelings for others. We are all human beings, subject to many pressures and anxieties, and full of many talents as well as shortcomings. To serve God loyally and faithfully while striving to overcome our own flawed and corrupt human natures, some areas of which involve lengthy private prayer and supplication to God as well as occasional public humiliation, is not an easy matter. Fortunately, God is merciful, but God will also not be mocked. Let us praise God for His mercy, and make sure that we do not mock Him with high-handed or presumptuous sin, lest we be made an example of because we would not be a good example ourselves.
 See, for example: