“וַיֹּאמֶר מֹשֶׁה אֶל־אַהֲרֹן וּלְאֶלְעָזָר וּלְאִיתָמָר בָּנָיו רָאשֵׁיכֶם אַל־תִּפְרָעוּ וּבְגָדֵיכֶם לֹא תִפְרֹמוּ וְלֹא תָמֻתוּ וְעַל־כָּל־הָעֵדָה יִקְצֹף וַאֲחֵיכֶם כָּל־בֵּית יִשְׂרָאֵל יִבְכּוּ אֶת־הַשְּׂרֵפָה אֲשֶׁר־שָׂרַף ה׳” (ויקרא י׳:ו׳).

“And Moses said to Aaron and to his sons Eleazar and Ithamar, ‘Do not bare your heads and do not rend your clothes, lest you die and anger strike the whole community. But your kin, all the house of Israel, shall bewail the fire that ה׳ has wrought’” (verse 6).

Why does Moshe say that the people will weep? דעת זקנים reads this as Moshe providing assurances to Aaron and his sons that the people will mourn for Nadav and Avihu. Aaron was concerned that if no one mourned for them, then the people would think that his sons had done something so wrong that they had forfeited their priestly status.

העמק דבר questions how Moshe could command the people to cry. Crying comes only from emotion. He explains that Moshe was not commanding the people to cry, but showing them how to cry. Haamek Davar differentiates between telling Aaron the people will cry “about the fire” instead of “over the fire.” Moshe tells the people they should cry over whatever causes them to be sad but do so directed at this event. The idea is that if one cannot muster the emotion to cry over a dead body, they should think about something that will cause them to cry and use that as motivation. In this way, the mourner will still honor the dead by weeping.

אור החיים does not see this as Moshe providing motivation, but instead Moshe explaining to the people that if they do weep for Aaron’s sons, then it will help prevent this tragedy from happening again. The crying “about the fire” means they should direct their mournful weeping to the cause of the death of the brothers.

For each of these interpretations, the undercurrent is that the people themselves may not have been motivated to weep for Aaron’s sons independently. Either Moshe had to command them in order to save face for Aaron, Moshe had to motivate them by providing advice on how to build up the emotion to cry, or Moshe had to motivate them with a promise that mourning would prevent this from happening in the future. None of the answers explain why the people would not spontaneously mourn. It is possible that the people were afraid of how to react. They had just witnessed fire descending from heaven consuming the sons of the Kohen Gadol. Frozen in a state of fear, they may not have known if it was okay for them to weep and mourn. For this reason, Moshe had to calm Aaron and coax the emotional reaction from the people.