The Midrash Rabba, at the beginning of Bamidbar, explains that the Torah was given to Bnai Yisroel with "aish umayim" (fire and water). Mayim, our chachamim assert, represents shiflus (humility), as they explain: "ma mayim manichin b'makom gavoa, v'holchin l'makom namuch, af divrei torah ainam mikaymin ela b'mi she'da'ato shefeila" - just as water leaves a higher level and goes to a lower level, so too the words of Torah are retained only by one who is humble. Aish (fire), however, which is constantly ascending, represents the confidence and assuredness of one who pursues Torah.
At once, we are challenged to balance the characteristics of aish and mayim. Balancing the statement of Avraham Avinu, "anochi affar v'eiffer" (Braishis 18:27) "I am but dust and ash", and the teaching of the mishna Sanhedrin (4:5) "l'fichach kol echad chayav lomar bishvili nivra ha'olam" - the conviction that the whole world was created for me.
Rav Asher Weiss explains that the sin of the meraglim (spies) and the rebellion of Korach va'adaso mark tragically improper applications of these middos (character traits).
Hakadosh Baruch Hu had promised and assured us of the successful conquest of Eretz Yisroel. The mergalim were called upon to embrace the middas ho'aish (trait of fire), to reflect confidence and conviction. Tragically, they felt dwarfed and humbled by the inhabitants of Canaan. "Vayehi b'ainenu k'hagavim, v'chein hayinu b'aineihem" (Bamidbar 13:33), "And we were as grasshoppers in our eyes and so we were in their eyes"; one must show the middas ho'aish and faithfully implement the ratson Hashem (will of Hashem).
Suddenly, with improper confidence and arrogance, Korach va'adaso challenge Moshe rabbeinu - "ki kol ho'eida kulam kedoshim u'b'tocham Hashem" (Bamidbar 16:3) ("for the entire congregation is holy, and Hashem is among them"). In the presence of Moshe and Aharon, one must adopt middas ha'mayim, deference and humility.
How different our history would have been had Bnai Yisroel internalized the confidence of middas ho'aish when confronting the ummos Ha'olam (nations of the world), and the middas ha'mayim in the presence of Moshe and Aharon.
We too must carefully balance these middos. When confronting the challenges of the outside world do so with the confidence of middas ho'aish. Internally, however, and especially in the presence of gedolei umanhigei yisroel embrace the humility of middas ha'mayim.