Why does the Torah declare the Shomer Chayav for Geneivah, when in Pasuk 7, it declared him Patur for Geneivah and Aveidah?
Rashi and Targum Yonasan: Because the earlier Parshah is referring to a Shomer Chinam who is only Chayav for Peshi'ah, whereas the current one is referring to a Shomer Sachar, who is only Patur from Onsin. 1
Why does the Torah use the double Lashon "Ganov Yiganev"?
What are the implications ofr the word "me'Imo"?
Mechilta: It exempts a Shomer who hands the sheep to a junior shepherd (which is normally done) but incorporates one who hands them over to a senior shepherd (which is not). 1
See Torah Temimah, note 140 and ha'Torah ve'ha'Mitzvah.
Why will a Shevu'ah not suffice to exempt the Shomer Sachar (like in Pasuk 10)?
Ramban #1: In fact, the Din is the same in both cases - If there are witnesses, the Shomer brings them to substantiate his claim, and if not, a Shevu'ah will suffice. And the Torah mentions witnesses here and a Shevu'ah above, because when the animal dies in its owner's domain or falls off a cliff 1 or is stolen by armed bandits, in all likelihood there are no witnesses; whereas when a lion or a bear attacks the herd, all the shepherds gather to try and stave it off.
Ramban #2 and Seforno: It is for the same reason that Isi ben Yehudah, commenting on Pasuk 9, extrapolates from "Ein Ro'eh" that if the Oneis occurs in a location where there are witnesses, then we do not rely on a Shevu'ah.