וַיֹּ֣אמֶר מֹשֶׁ֣ה אֶֽל־אַהֲרֹ֡ן וּלְאֶלְעָזָר֩ וּלְאִֽיתָמָ֨ר ׀ בָּנָ֜יו רָֽאשֵׁיכֶ֥ם אַל־תִּפְרָ֣עוּ ׀ וּבִגְדֵיכֶ֤ם לֹֽא־תִפְרֹ֙מוּ֙ וְלֹ֣א תָמֻ֔תוּ וְעַ֥ל כָּל־הָעֵדָ֖ה יִקְצֹ֑ף וַאֲחֵיכֶם֙ כָּל־בֵּ֣ית יִשְׂרָאֵ֔ל יִבְכּוּ֙ אֶת־הַשְּׂרֵפָ֔ה אֲשֶׁ֖ר שָׂרַ֥ף יְהוָֽה׃
I rzekł Mojżesz do Ahrona, i do Elazara i Ithamara, synów jego: "Głów waszych nie obnażajcie, a szat waszych nie rozdzierajcie, abyście nie pomarli, a Bóg nie rozgniewał się na zbór cały. Ale bracia wasi, wszystek dom Israela niech opłakuje ten pożar, który rozpalił Wiekuisty.
Zohar
The firstborn Nadab stands on his own merits and Abihu rests on his own, that each one are considered in the eyes (of the Torah) as both Elazar and Itamar (combined). But Nadab and Abihu by themselves are each considered equal to the seventy members of the Sanhedrin who served before Moses. For this reason, their deaths atoned for Yisrael. Therefore, it is written, "But let your brethren, the whole house of Yisrael bewail the burning" (Vayikra 10:6). Rabbi Shimon said: "Nadab the firstborn," meaning he is the one that all acclaim and praise are his. How much more so with Nadab and Abihu (together), because these two have no equal among all Yisrael.