This verse indicate that they offered “unauthorized” (zār) fire before the Lord. The term zār has a broad range of meaning. It is used to describe those who are foreigners or non-Hebrews (e.g., Exodus 29:33), but the word is also used to refer to something that is illegitimate or prohibited (e.g., Exodus 30:9). This has made the exact details of Nadab and Abihu’s actions highly debated. Some have suggested that these brothers were introducing pagan practices into the worship of the true God. Others have claimed they entered the Most Holy Place of the tabernacle, an area where they were not allowed. What is clear is that they were making an offering in a different way from that which God had prescribed. Ross concludes, “What exactly their sin was is hard to determine. They profaned the holy things with unholy things, and so basically they were disobedient.”¹