Who was Nadab?
Nadab was Aaron's oldest son by Elisheba (Exo. 6:23; Num. 3:2). With Aaron and Abihu and 70 elders he had the privilege of nearer access to Jehovah at Sinai than the mass of the people, but not so near as Moses (Exo. 24:1).
Struck dead for kindling (probably under intoxication) the incense with "strange fire," not taken from the perpetual fire on the altar (Lev. 6:13; 10:1-10).
IBSE, "Isaac" (in the public domain) with minor edits.