Question: "Who were Nadab and Abihu?"
Answer: Nadab and Abihu were the oldest and second oldest sons of Aaron, the brother of Moses and first high priest of Israel. Their relation to Aaron is mentioned in Numbers 3:2–3 as two of Aaron’s four sons: “The names of the sons of Aaron were Nadab the firstborn and Abihu, Eleazar and Ithamar. Those were the names of Aaron’s sons, the anointed priests, who were ordained to serve as priests.”
Exodus 24 includes Nadab and Abihu as two of the leaders of Israel who came before the Lord. They were given the special privilege of seeing a vision of God: “Moses and Aaron, Nadab and Abihu, and the seventy elders of Israel went up and saw the God of Israel. Under his feet was something like a pavement made of lapis lazuli, as bright blue as the sky. But God did not raise his hand against these leaders of the Israelites; they saw God, and they ate and drank” (Exodus 24:9–11).
Nadab and Abihu are best known, however, for offering “unauthorized fire” (or “strange fire,” KJV) before the Lord in the tabernacle and dying as a result. Leviticus 10:1–2 shares this sobering account, stating, “Aaron’s sons Nadab and Abihu took their censers, put fire in them and added incense; and they offered unauthorized fire before the LORD, contrary to his command. So fire came out from the presence of the LORD and consumed them, and they died before the LORD.”
Why did God put Nadab and Abihu to death? Leviticus 10:3 offers the explanation: “Moses then said to Aaron, ‘This is what the Lord spoke of when he said: ‘“Among those who approach me I will be proved holy; in the sight of all the people I will be honored.”’” Those who served as priests before the Lord were required to serve Him honorably. If they did not, the consequence was death. In the case of Aaron’s sons, they dishonored the Lord by disobeying His command to only use fire from the brazen altar in the tabernacle (see Leviticus 16:12). The “unauthorized fire” they offered was taken from another source.
A similar penalty can be found when David and the Israelites attempted to move the Ark of the Covenant to Jerusalem from Kiriath Jearim (1 Chronicles 13:1–10). When the ark started to fall over, a man reached out and touched the ark to catch it, and he was immediately struck dead. Why? He was not one of the Levites God had authorized to serve in this sacred, reserved role (Deuteronomy 31:25; 1 Chronicles 15:2).
It may be difficult to understand such strict views regarding ceremony in our time, but these ways were part of how God revealed Himself as holy to the people of Israel. With the coming of Jesus, we find a fulfillment of the Law (Matthew 5:16) and the curtain of the temple torn in two, offering direct access to God through Jesus Christ (Hebrews 10:20). God continues to reign in perfect holiness, and all who come to Him through Christ are made part of “a royal priesthood” (1 Peter 2:9).