Among the sins for which they had to atone was their great pride, which was expressed in several ways. They did not marry, because they considered no woman good enough for them, saying: "Our father's brother is king, our father is high priest, our mother's brother is prince of his tribe, and we are heads of the priests. What woman is worthy of us?" And many a woman remained unwed, waiting for these youths to woo her.
In their pride they even went so far in sinful thoughts as to wish for the time when Moses and Aaron should die and they would have the guidance of the people in their hands. But God said: "'Boast not thyself of to-morrow;' many a colt has died and his hide had been used as cover for his mother's back." Even in the performance of the act that brought death upon them, did they show their pride, for they asked permission of neither Moses nor Aaron whether they might take part in the sacrificial service.
What is more, Nadab and Abihu did not even consult with each other before starting out on this fatal deed, they performed it independently of each other. Had they previously taken counsel together, or had they asked their father and their uncle, very likely they would never have offered the disastrous sacrifice. For they were neither in a proper condition for making an offering, nor was their offering appropriate.
They partook of wine before entering the sanctuary, which if forbidden to priests; they did not wear the prescribed priestly robes, and, furthermore, they had not sanctified themselves with water out of the laver for washing. They made their offering, moreover, in the Holy of Holies, to which admittance had been prohibited, and used "strange fire," and the offering was all in all out of place because they had had no command from God to offer up incense at that time.
Apart from this lists of sins, however, they were very pious men, and their death grieved God more than their father Aaron, not alone because it grieves God to see a pious father lose his sons, but because they actually were worthy and pious youths.