Why should you lift your eyes?
Radak: Look at the stars - they are awesome bodies. Think - who created them? Man should understand that the world was created - nothing can create itself - and that there was only one Creator.
Malbim: If you want to have a something to compare to Me, look at the awesome spheres above, or the angels who move them. However, see (understand) that they are creations, and do not resemble the Creator.
What does "Eleh" refer to?
Rashi: The legion that you see above.
Why does it say "ha'Motzi v'Mispar Tzeva'am"?
Radak: Only Hashem can count the stars. Astronomers agree that there are 1098 stars, i.e. big stars that illuminate on the land. In all there are too many stars for man to count. Hashem counts them and gives to each a name based on the reason it was created - "Moneh Mispar la'Kochavim l'Chulam Shemos Yikra" (Tehilim 147:4). Each has power and authority over a creation below - 'there is no grass that does not have a Mazal above that hits it and tells it to grow - "ha'Yadata Chukos Shamayim Im Tasim Mishtaro va'Aretz"' (Iyov 38:33; Bereishis Rabah 10:6).
Malbim: The stars have a fixed number; they do not reproduce.
What is the meaning of "b'Shem Yikra me'Rov Onim v'Amitz Ko'ach"?
Radak: The names that Hashem calls to the stars are based on their powers over creations below. They do not perish or weaken; they remain forever like they were created. From this, a person will recognize the Creator. "Ha'Lo Sed'u ha'Lo Sishma'u... ha'Lo Havinosem" (21); "lift your eyes u'Re'u", i.e. see (understand) in the heart. It says about one who knows how to calculate Tekufos and Mazalos, but does not, "v'Es Po'al Hashem Lo Yabitu u'Ma'aseh Yadav Lo Ra'u" (5:12; Shabbos 75a). It is a Mitzvah to calculate Tekufos and Mazalos (ibid.) - "u'Shmartem va'Asisem Ki Hi Chachmaschem u'Vinaschem l'Einei ha'Amim" (Devarim 4:6) - Tekufos and Mazalos is the Chachmah that can be shown to Nochrim. If one knows how to calculate Tekufos and Mazalos, but does not do so, others may not talk with (Ben Yehoyada - highly about) him. (75a).
Malbim: Each one's name is based on its action - e.g. Shabtai destroys, Tzedek does Tzedakos, Ma'adim murders. It cannot change its action. The individual stars persist, not due to their own strength, rather, me'Rov Onim of their Creator.