Right after the fire burned the Korbanos, it says that a fire burned: נָדָב וַאֲבִיהוּא Nadav and Avihu also. RSRH explains that the whole idea of a Korban is to be Mach'nia to Hashem, and by inventing their own Korban in their original way, they were doing just the opposite of the whole Tachlis of a Korban. (By the way, a Korban is always a docile: נִרְ דָף persecuted animal (Chazal) who takes orders and doesn’t have his own ideas).
Indeed, there is a time and place to Davka be M’chadesh, like when Moshe Rabeinu broke the Luchos on his own initiative, and Hashem was pleased. (Rashi). (Maybe: נָדָב וַאֲבִיהוּא Nadav and Avihu had this Inyan in mind, and were mistaken in this particular case). When a person brings a Korban, he is saying: “This Shechita should have been me, since I’m a nobody. But this animal is instead, and therefore it saves me”. Hashem showed from day one how a person can be the Korban itself, Chas V'shalom, when he’s missing Hachna'a.
How important it is to be Mach'nia, especially with relationships; it saves you a trip to the hospital, Chas V'shalom. Be smart! Give in and live long, like it says: וַעֲנָוִים יִירְ שׁוּ אָרֶץ תהלים לז יא the humble will inherit the earth (and delight in abundant peace).
Chazal say many reasons for the tragedy of Nadav and Avihu
Some say they had drunk wine, which disqualifies a Cohen from doing Avoda. Some say they were guilty of: מוֹרֶה הַ לָ כָה בִ פְ נֵּ י מֹּ שֶׁ ה רַבָּן issuing a halachic decision in the presence of their Rebbe, Moshe, which is Chayav Missa. Some say they wanted to take over Moshe and Ahron’s positions, hoping they would die. (Of course, we have no understanding of these giants).
Yet, all Moshe mentions is: בִקְרֹּבַי אֶקָדֵּשׁ Hashem is sanctified (honored and feared) through those who are closest to Him. All he sees is their greatness, that they were chosen as a lesson, how careful we must be with the Mishkan, and it is a Simcha for Ahron to have had such great sons, who were even greater than Moshe and Ahron. (Chazal).
Notice how Moshe sees only positive and goodness, and he ignores all negative! A true Ayin Tova has no room in his head to get involved in: רַע bad, he is full of love and positivism and Bitachon.
