Moshe Taught Klal Yisroel How to be Humble:
Sefer Ohr L’Shamayim explains this pasuk by citing the Zohar Hakadosh (Chelek Aleph 122B) that says: “A small person is big (in his own eyes), and a big person is small (in his own eyes.)”
The Zohar is stressing the importance of anavah. If one acts humbly, he will succeed in life, as this is the way to connect to Hashem. Hashem created the world as “yesh m’ayin” (something from nothing). So too, one who follows the ways of Hashem should embrace the middah of “ayin” (considering himself to be nothing). He should always see himself as unworthy. If he does so, he will merit the fulfillment of the dictum of Chazal (Shabbos 156A): “Ayin mazal l’Yisroel” – which can be understood to mean that if one is “ayin”, he will have good mazal in Klal Yisroel.
Accordingly, he explains the pasuk to mean that Moshe spoke to the “roshei hamatos” (heads of the Shevatim). This can be translated as saying that although they were the heads, they still were “matos”, on the bottom – meaning that they were lowly and humble. They learned this way of acting from Moshe, who always behaved this way.
