What is the meaning of "Lo mi'Motza umi'Ma'arav"?
Rashi: From [the east, from] where the sun comes out (rises), and from [where it sets, in] the west.
Radak: Refer to 75:7:2:2.
Radak citing his father: "Umi'Ma'arav" refers to business, like "v'Orvei Ma'aravech" (Yechezkel 27:27). Motza is the appointment of kings. Mi'Midbar is [eloquent speech,] like "u'Midbarech Navah" (Shir ha'Shirim 4:3). These are three ways in which a person is aggrandized - royal appointment, business or eloquent speech.
Malbim: This is why I told Resha'im not to raise their horns, because elevation is not due to man; it, and descent, are from Hashem. One cannot raises himself. If he tries, Hashem lowers him! Early Chachamim said that most mountains are in the extreme north and south of the world, which are not settled due to the great cold. The desolation is the reason for the mountains! Later Chachamim said that most mountains are near the equator, east and west. The earth rotates rapidly every day, and this causes most things to move towards the middle, where it rotates most rapidly. Really, there is no concentration of mountains near the poles, or near the equator. Elokim Shofet (verse 8) decreed where they will be! This is a lesson that elevation is not from nature; it is from Hashem's decree.
Why does it say "v'Lo mi'Midbar Harim"?
Rashi: [Also] from the wildernesses to which you go in caravans to increase wealth, you may not raise your horns.
Radak: Greatness and elevation does not come to a person from the east, west [or Midbar. Rather, Hashem lowers and rises - verse 8]. "Harim" is an expression of raising. There is Kamatz under the Beis in mi'Midbar, for it is not Samuch [to Harim]. `
Radak citing Tanchuma Matos 6: Every Harim in Tanach, except for this, refers to mountains. Here it teaches that a person is not elevated in these ways (going out to Midbaros).
Mesilas Yesharim Perek 21: Hishtadlus (effort) does not help, just it is necessary. Once one did Hishtadlus, he fulfilled his obligation, and there is room for Shamayim's Brachah to rest on him. He need not waste his days with diligence and Hishtadlus.
Malbim: Refer to 75:7:1:4.
