THE DEATH OF NADAB AND ABIHU

Now Nadab and Abihu, the sons of Aaron, took their respective [ceremonial] censers, put fire in them, placed incense on it and offered strange (unauthorized, unacceptable) fire before the LORD, [an act] which He had not commanded them to do.
And fire came out from the presence of the LORD and devoured them, and they died before the LORD.