1 Chronicles 6:1-3
v1  The genealogy of Levi is given, his sons were: Gershon, Kohath and Merari.
v2 Kohath was the father of Amram, Izhar, Hebron and Uzziel.
v3 The children of Amram were Aaron, Moses and Miriam.

  The sons of Aaron were Nadab, Abihu, Eleazar and Ithmar.
  Sometimes children are a disappointment to their parents and even to God.
  Nadab and Abihu were not only a disappointment but were punished by God for willful disobedience as priests.

  What did they do?
Leviticus 10:1 Nadab and Abihu were priests who served in the temple.  They drank strong drink  until they were drunk then offered a sacrifice by fire to the LORD that God had not commanded.

  Both men were willfully and deliberately disobedient to God’s way to worship Him.

  All who worship the living God are to do it according to His terms.  Obedience to God is better than any man-made sacrifice.

  Sudden death was the penalty God dealt these two men.  Their high positions did not save them.  Willful disobedience to God results in God’s judgment.

  What caused these two priests to act in such a way?
  Leviticus 10:9-11 Moses told Aaron and his two remaining sons “Do not drink wine or strong drink, neither you nor your sons with you, when you come into the tent of meeting, so that you will not die – it is a perpetual statute throughout your generations –
10 and so as to make a distinction between the holy and the profane, and between the unclean and the clean,
11 and so as to teach the sons of Israel all the statutes which the LORD has spoken to them through Moses.’”

Consider this  ~

God deserves our true and holy worship.
He is holy.
Listen to Him.