Leviticus 10:1 And Nadab and Abihu, the sons of Aaron, took either of them his censer, and put fire therein, and put incense thereon, and offered strange fire before the Lord, which he commanded them not.
[Patriarchs & Prophets pp 359] After the dedication of the tabernacle, the priests were consecrated to their sacred office. These services occupied seven days, each marked by special ceremonies. On the eighth day they entered upon their ministration. Assisted by his sons, Aaron offered the sacrifices that God required, and he lifted up his hands and blessed the people. All had been done as God commanded, and He accepted the sacrifice, and revealed His glory in a remarkable manner, fire came from the Lord and consumed the offering upon the altar.
The people looked upon this wonderful manifestation of divine power with awe and intense interest. They saw in it a token of God's glory and favor, and they raised a universal shout of praise and adoration and fell on their faces as if in the immediate presence of Jehovah. But soon afterward a sudden and terrible calamity fell upon the family of the high priest. At the hour of worship, as the prayers and praise of the people were ascending to God, two of the sons of Aaron took each his censer and burned fragrant incense thereon, to rise as a sweet odor before the Lord.
But they transgressed His command by the use of “strange fire.” For burning the incense they took common instead of the sacred fire which God Himself had kindled, and which He had commanded to be used for this purpose. For this sin a fire went out from the Lord and devoured them in the sight of the people.
Leviticus 10:2 And there went out fire from the Lord, and devoured them, and they died before the Lord. 3 Then Moses said unto Aaron, This is it that the Lord spake, saying, I will be sanctified in them that come nigh me, and before all the people I will be glorified. And Aaron held his peace.
May God add his blessing to the study of His word. “Good night” and God bless!