Nadav and Avihu’s action was clearly in violation of the norm. These two tzaddikim, righteous persons, did not plan on sinning against Hashem. They were of the opinion that their initiative was appropriate and even commendable. Wherein lay the difference between their position and that of Moshe Rabbeinu? While the commentators enumerate a number of areas in which they could have been lacking (clearly relative to their exalted spiritual status), the Talmud (Eiruvin 63a) underscores two: they entered the Sanctuary while intoxicated with wine; they rendered a halachic decision in the presence of their Rebbe, Moshe. Both of these seeming indiscretions require elucidation. First, in what area did they disagree with their Rebbe? Second, why would they enter the Sanctuary while inebriated? What spiritual advantage would this afford them?
The Sefas Emes explains that Nadav and Avihu sought to achieve angel status, through which (like angels) they would perceive the ratzon, will, of Hashem without waiting for Him to command them. They hypothesized that when Klal Yisrael responded to the Giving of the Torah with a resounding Naase v’nishma, “We will do and we will listen,” they were intimating that they were prepared to do/act without even receiving a prior command or authorization. We perceive what is Hashem’s will, and we immediately act. Moshe Rabbeinu disagreed. He understood that Judaism is a discipline based on carrying out Hashem’s command.
Why did they enter the Sanctuary while intoxicated? They felt that wine expands the mind, thus allowing for greater, more intense perception of the Divine. Wine would allow them to go beyond the normal scope of understanding.
Horav Moshe Pick, zl, expands upon the words of the Sefas Emes. He asserts that Nadav and Avihu’s understanding of the Rabbinic maxim (Kiddushin 31a), Gadol ha’metzuvah v’oseh mimi she’eino metzuvah v’oseh; “Greater is the one who is commanded and does it than one who is not commanded – yet still does it,” contrasts with Moshe’s understanding of it. Nadav and Avihu felt that this maxim applied to one who has achieved extreme level of spirituality. On their spiritual plateau, perceiving what Hashem wants and acting upon it is yet greater than waiting for prior authorization. To act on one’s own volition is, in their opinion, the hallmark of service to Hashem. Moshe (like Avraham Avinu who did not circumcise himself until Hashem commanded him to do so) disagreed. Their contrasting opinions went back to their divergent understanding of Klal Yisrael’s declaration, Naase v’nishma. Were they advocating acting without prior command or rationale?
Why did they drink wine prior to performing the service? Wine makes one happy: V’yayin y’samach levav enosh, “And wine gladdens the heart of a man” (Tehillim 104:15). They waited to serve Hashem amid unbridled joy. Wine would enable them to do so. Moshe, however, taught that the only true joy can be derived from fulfilling Hashem’s mitzvah. Carrying out the Almighty’s command is our greatest joy. Wine is a substitute, but does not provide the real experience.