Nadab and Abihu were the two eldest sons of Aaron (Exodus 6:23). Additionally, these brothers were Moses’ nephews. Previously, they were singled out to join Moses and Aaron on Mount Sinai (Exodus 24:1–2). The Lord even appointed them to be leaders within the priesthood (Exodus 28:1). Along with their brothers, Eleazar and Ithamar, they had just been ordained as priests to facilitate the worship of the Lord in the tabernacle (Leviticus 8:30). As such, Nadab and Abihu would have been next in line to succeed Aaron as the high priest. Nadab and Abihu were authorized and commissioned to safeguard the worship of the Lord. These brothers would have been respected and honoured within Israel.
1 Now Nadab and Abihu, the sons of Aaron, each took his censer and put fire in it and laid incense on it and offered unauthorized fire before the LORD, which he had not commanded them.