1 Then Aaron’s sons, Nadab and Abihu, each took his fire pan and put fire in it, set incense on it, and presented strange fire before the Lord, which he had not commanded them to do. 2 So fire went out from the presence of the Lord and consumed them so that they died before the Lord. 3 Moses then said to Aaron, “This is what the Lord spoke: ‘Among the ones close to me I will show myself holy, and in the presence of all the people I will be honored.’” So Aaron kept silent. 4 Moses then called to Mishael and Elzaphan, the sons of Uzziel, Aaron’s uncle, and said to them, “Come near, carry your brothers from the front of the sanctuary to a place outside the camp.”

This divine statement was made to Moses on Mount Sinai, but he himself did not understand it until the incident of Nadab and Abihu occurred. When, just before that incident, God was made present to the people (Leviticus 9:24)] Moses said to God: 'Master of the Universe, who is there more beloved [to You] than me and my brother Aaron? [Are we not the ones] by whom this house will [now] be sanctified?' After Aaron's two sons entered to sacrifice and came out burnt, Moses [now understood and] said to Aaron, 'Aaron my brother, your sons died for the sake of sanctifying God's name. That is what He meant by 'I will be made holy by those who are near [and dear] to me [that is, Nadab and Abihu] and then, as a result before all the people I will be honored' [Leviticus 10:3]