What exactly did Moshe mean when he said "P'nu u'Se'u ha'Midbarah ... "?
Rashi: He meant that, instead of traversing the width of Edom from south to north to enter Eretz Cana'an, they were to retrace their steps, to return towards the Yam-Suf 1 , and travel along the south of Har Se'ir, from west to east.
Rashi (on 2:1): From where they left Egypt, south-west of Eretz Cana'an
QUESTIONS ON RASHI
Rashi writes that we should have traversed the width of Edom to enter Eretz Kena'an. Edom did not allow us to pass through, and we were not allowed to fight them (2:5, Bamidbar 20:18)!