What are the ramifications of "P'nu lachem Tzafonah"?
Rashi: 'Turn towards the north, and travel along Edom's eastern border'. 1
Rashbam: It means turn northwards towards Eretz Yisrael. 2
Kli Yakar (from Devarim Rabah 1:19): Hatzpinu (hide) yourselves (your wealth). Edom has more jealousy of Yisrael than any other nation; they think that Yakov stole Esav's Brachah. Yakov told his sons "Lamah Tisra'u" (Bereishis 42:1)
Why does it say "Rav Lachem Sov Es ha'Har ha'Zeh"?
Da'as Zekenim, Rosh: This was Esav's reward 1 for saying "Yesh Li Rav" (I do not need your (Yakov's) gift).
Rosh (citing Devarim Rabah 1:15) and Targum Yonasan: Esav honored his father greatly. He even had special clothes to serve him. Therefore, we were not allowed to fight Edom. 2
Alshich: You had great misfortune being next to this evil neighbor - Aharon died due to Yisrael's extra approach to Edom (refer to Bamidbar 20:23:1:1 and the note there).
Yalkut Shimoni (806) implies that the reward was that we turned away from Edom. R. Bechayei implies that his reward was that we did not fight Edom all these years. (Perhaps the benefit was that we bought food and water from them (verse 6) during those many years!