“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 LORD, which He had not commanded them. So fire went out from the LORD and devoured them, and they died before the LORD. And Moses said to Aaron, “This is what the LORD 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.”
— Leviticus 10:1-3 NKJV
The position of priest was to not be taken lightly. There were specific instructions that were to be followed and not deviated from. Nadab and Abihu chose to deviate from those instructions. It cost them their lives.
Moses reminded Aaron of the L-RDs instruction. As a pastor/teacher, we must be careful to follow the L-RDs instructions and not deviate from them. We must always regard the L-RD as holy. We must remember that it is G-d who placed us in the position that we are in. It is also G-d who called us. It is also G-d who brought together the congregation that is before us. Nothing of ourselves. Therefore we must always glorify the L-RD individually in our personal time with Him, as well as before all the people. The L-RD is holy and He must be glorified. We can see an example of this with David before the Israelites in 1 Chronicles 29:1-18. As we glorify the L-RD, the congregation will follow.
G-d is holy and all His decisions are right and true. There are consequences for those that disobey the L-RD and we must hold our peace when someone reaps the consequences for their actions as the L-RD carries out their punishment. He is the L-RD and He is Holy.