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. And fire came out from before the LORD and consumed them, and they died before the LORD.
This could not be any more dramatic. This episode occurs right after God has accepted the consecrated work of Aaron and his sons as priests.This incident was a painful variation from normal pattern of obedience that had been Israel’s story up to this point. At the end of chapter nine fire comes out from God to consume the sacrifice (showing His approval). The very next set of verses in chapter ten show fire coming out from God to consume the priests! I think God was not happy!
Why? What had Nadab and Abihu done that warranted such extreme and immediate judgment? There are three possible explanations for their actions which are simply called “unauthorized”. They were offering incense before the Lord. They may have used coals that were not from the prescribed source. They may have offered the incense at the wrong time of day. It is clear that this was not unintentional, but a deliberate violation, which has led some scholars to suggest that the command in Leviticus 10:9 that the priests avoid wine or strong drink points to the fact that they came before the Lord in a drunken state, making a mockery of their priestly duties. Again, all three show a deliberate disregard for the holiness of God, and dramatic judgment is the result.
God will be taken seriously. That is the point of the text. And if He is not, human beings who disregard Him will have to deal with the consequences. To obey Him brings blessing and awesome power at display among His people. To disobey Him brings judgment and awesome power is displayed then as well. Either way God gets glorified. He is glorified in both reward for obedience, and judgment for sin.