Nadab and Abihu sinned knowingly against God by offering strange fire before the Lord and were fiercely judged by Him because He was not sanctified in them when they came near Him and because He was not glorified before all the people:
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. 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.
We know with certainty that what they offered was not what God had commanded to be offered to Him. This account plainly reveals to us that human sinfulness extends to what sinful humans have chosen to do in the worship of the true God that was in actuality worship that was not acceptable to Him because what was done was against what He had commanded to be done.
Many Christians deny that these truths apply to what kinds of instrumental music humans offer in worship. Rather, they hold that all kinds of instrumental music are acceptable to God for use in worship and that human sinfulness does not extend to the kinds of instrumental music that people offer to God.
