What does the verse teach?
Rashi: A small amount of people coming to help Tzadikim (to help Avraham fight the four kings) are better than multitudes of Resha'im (the four kings' armies).
Radak #1: A Tzadik is happy with the small amount that he has from this world, and it suffices for him. Resha'im are not happy with their vast wealth. They want more, and they are never satisfied - "Tzadik Ochel l'Sova Nafsho u'Veten Resha'im Techsar" (Mishlei l3:25). Also, a Rasha's wealth harms him; he becomes haughty over people, until they rise against him and kill him, and take all his wealth.
Radak #2: A small amount [of people] with a Tzadik is better than many nobles with Resha'im. "Rabim" are great, like "v'Rabei ha'Melech" (Yirmeyah 41:1).
Malbim: A small amount [of strength] of the Oni is better than multitudes of Resha'im. Their great troops and helpers do not help them to harm a Tzadik!
Orchos Tzadikim (Sha'ar ha'Anavah DH Harbeh): A Tzadik is happy with the portion that Hashem gave to him, be it much or little. This quiets his heart from distractions of this world (trying to increase wealth), and his heart is free for Torah, Chochmah and Avodas Hashem.
What is the meaning of "Hamon"?
Rashi: It is multitudes. Radak - it is the opposite of Me'at mentioned about a Tzadik.
Radak: "Hamon" is like Mamon - "u'Mi Ohev be'Hamon" (Koheles 5:9). "Rabim" is plural, even though it refers to Hamon, which is singular. We find like this - "v'Kibel ha'Yehudim" (Esther 9:23).
