What are "Mevorachav"?
Rashi: They are those whom Hashem, the Tzadik of the world, blesses. Radak - these are the Temimim mentioned above (verse 18). Because they are gracious, give and are generous, Hashem gives to them wealth and honor, and blesses them.
Malbim: Birkas Hashem is on a Tzadik. It brings wealth, and does not bring sadness with it.
Why do they inherit the land?
Radak: This means that their success will endure, like an inheritance from father to son.
Who are "Mekalelav"?
Radak: They are the Resha'im, who are stingy; they do not even pay what they borrow!
How will they be cut off?
Radak: Their wealth will not endure. They will lose their wealth and good, and be cut off from this world and the world to come.
