Sameach B'chelko Is the True Wealth in This World and The True Avodas Hashem

The Me'am Lo'ez [quoting the Alshich] says that Moshe kept referring to them as “Bnei Levi”, because he was reminding them that they were Chashuvim who weren’t involved in Chet HaEigel and the Meraglim. “It’s not fitting for you to get involved in such lowlife sins like Machlokes!” We have a lesson how to give Tochacha.

The main complaint that Moshe had against Korach and his flock was that they weren’t Sameach B'chelko. He was the perfect מֹוכִיחַ one to give Mussar for this, since he himself hated שְרָרָה prominence, and he even got punished when he persisted in refusing to become the leader of Klal Yisroel. Moshe truly hated Kavod, and he was the perfect מֹוכִיחַ one to give Mussar in this area.

Moshe and Ahron were A-1 Sameach B'chelko, which is #1 in all Avodas Hashem, as it says after the punishments of the Tochacha: תַחַת אֲשֶר לֹא עָבַדְתָ אֶת ה' אֱֹלקֶיךָ בְשִמְחָה (Ki Savo 28:47) Since you did not serve Hashem with Simcha. Perhaps this is why Ketores was chosen as the “test” to see who is fit for the Kehuna. All other Korbanos are: רֵיחַ נִיחֹוחַ לַה' an appeasing fragrance to Hashem. Although they don’t smell good, they are considered a Geshmake fragrance, since the person who brings the Korban is doing Ratzon Hashem. But only Ketores is literally רֵיחַ נִיחֹוחַ actually has a good smell. Perhaps it is a symbol of עִבְדּו אֶת ה' בְשִמְחָה serving Hashem with Simcha.

Chazal say: אֵין הַשְכִינָה שֹורָה אֶלָא עַל חָכָם גִבֹור וְעָשִיר (Shabbos 92a) The Shechina rests only on a person who is a Chochom, a Gibbor, and an Ashir [one who is wealthy]. These criteria are all meant to be understood literally; i.e. someone who is wise, strong, and wealthy; and they can also mean: אֵיזֶהּו עָשִיר הַשָמֵחַ בְחֶלְקֹו the true wealth; one who is happy with what he has; אֵיזֶהּו גִבֹור הַכֹובֵש אֶת יִצְרֹו true strength; one who has control over his desires. etc.