1)
Why does it teach here that Hashem will not starve Nefesh Tzadik?
1.
Rashi (2): If you will say, if a Tzadik will give from his property to Tzedakah, how will he have what to eat? (Our verse teaches that he will not be hungry.)
2.
Malbim: At a time of hunger, storehouses [of money] do not help, for there is no grain to buy. Still, a Tzadik will not starve - "uvi'Ymei Ra'avon Yisba'u" (Tehilim 37:19). "Nefesh Tzadik" teaches that Hashem will give to him all desires of his Nefesh.
2)
What is "Havas"?
1.
R. Yonah: It is the Aveirah of oppressing others.
2.
Malbim: It is breakage.
3)
How will it push him?
1.
Rashi: It will make him fall.