Father of Him; i.e., “worshipper of God”, the second of the sons of Aaron (Ex. 6:23; Num. 3:2; 26:60; 1 Chr. 6:3). Along with his three brothers he was consecrated to the priest’s office (Ex. 28:1). With his father and elder brother he accompanied the seventy elders part of the way up the mount with Moses (Ex. 24:1,9). On one occasion he and Nadab his brother offered incense in their censers filled with “strange” (i.e., common) fire, i.e., not with fire taken from the great brazen altar (Lev. 6:9, etc.), and for this offence they were struck dead, and were taken out and buried without the camp (Lev. 10:1-11; comp. Num. 3:4; 26:61; 1 Chr. 24:2). It is probable that when they committed this offence they were intoxicated, for immediately after is given the law prohibiting the use of wine or strong drink to the priests.
Abihu
Abihu was one of four sons born to Aaron and Elisheba, and he served alongside his brother Nadab. Then, in Leviticus 10, comes a sudden and sobering scene: the two took their censers and “offered strange fire before the LORD, which he commanded them not.” Fire came out from the LORD, and they died. Numbers 3:4 repeats the account and adds that they left no children, so Eleazar and Ithamar carried on as priests. Readers differ on exactly what made the fire strange, but the passage plainly says it was something God had not asked for. Start with Leviticus 10:1-3 and read the verses that follow.
4 verses
Exodus
And Aaron took him Elisheba, daughter of Amminadab, sister of Naashon, to wife; and she bare him Nadab, and Abihu, Eleazar, and Ithamar.
Leviticus
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.
And there went out fire from the LORD, and devoured them, and they died before the LORD.
Numbers
And Nadab and Abihu died before the LORD, when they offered strange fire before the LORD, in the wilderness of Sinai, and they had no children: and Eleazar and Ithamar ministered in the priest's office in the sight of Aaron their father.
From Easton's Bible Dictionary
Matthew George Easton, 1897