Why does the Torah insert the (otherwise superfluous) word "Kol Tzipor Kanaf"?
Chulin, 139b: "Tzipor" incorporates Tahor birds; "Kanaf" includes Tamei birds and locusts.
What are the implications of "u'Fen Tisa Einecha ha'Hashamaymah"?
Rashi: It implies that one may not look at them with the intention of straying after them. 1
See Sifsei Chachamim.
What does the Torah mean when it writes "asher Chalak Elokecha osam Hashem le'Chol ha'Amim"?
Rashi #1 and Rashbam #1: It means that Hashem gave the luminaries to the nations to illuminate the world on their behalf. 1
Rashi #2, Rashbam #2 and Targum Yonasan: It means that He did not prevent them from straying after (worshipping) them as gods - on the contrary, He made it possible for them 2 to stumble with their nonsense 3 on order to drive them out of the world. 4
Ramban: With reference to the stars and the constellations, it refers to the 'angel' of each and every nation, which the nations subsequently adopted as gods and worshipped. 5
Seforno: He distributed the luminaries to serve the world in an orderly fashion, based on the needs of the different lands and their inhabitants. 6
See Totrah Tmimah, citing Megilah, 9b - that this was the change that the seventy-two elders made for King P'tolomy, and the explanation according to the original text concurs with answer #2.
Rashi: But not Yisrael, whom He took out of Egypt in order to be their G-d, as the Pasuk goes on to explain.
See Torah Temimahh, note 41.
Rashbam: As the Pasuk intimates in Tehilim, 26:3.
Ramban: Which is why the Torah writes in Pasuk 20 "But you, Hashem took (for Himself)", implying that Yisrael are the nation of Hashem, who do not have (who do not need) a celestial power to lead them. See Ramban who elaborates.
Seforno: Something that could not possibly have happened by itself. See Seforno.
Why does the The Torah switch from "Pen Tashchisun" (in Pasuk 15) to "Venidachta ... "?
Oznayim (on Pasuk 15): Because the term 'Hashchasah' (corruption) is applicable with regard to worshiping creatures that are inferior to, or on the same level as oneself, but not to superior creatures 1 such as the sun, the moon and the celestial beings. 2
Because the term "Venidachta" is applicable to the celestial beings, which one actually worships, but not to people, animals, birds, vermin and fish, whose image one is worshiping, but not the creatures themselves. 3