וַנֵּ֜פֶן וַנִּסַּ֤ע הַמִּדְבָּ֙רָה֙ דֶּ֣רֶךְ יַם־ס֔וּף כַּאֲשֶׁ֛ר דִּבֶּ֥ר יְהוָ֖ה אֵלָ֑י וַנָּ֥סָב אֶת־הַר־שֵׂעִ֖יר יָמִ֥ים רַבִּֽים׃ (ס)
Dann drehten wir uns um und machten uns auf den Weg in die Wüste auf dem Weg zum Roten Meer, als der Herr zu mir sprach. und wir umrundeten den Berg Seir viele Tage.
Rashi on Deuteronomy
ונפן ונסע המדברה THEN WE TURNED AND JOURNEYED INTO THE WILDERNESS — If they had not sinned, they would have passed by the way of Mount Seir to enter the Land from its south to its north, but because they became degenerate they had to turn towards the wilderness which is between the Red Sea and the south of Mount Seir, and they proceeded along its southern side from the west to the east, דרך ים סוף BY THE ROUTE FROM THE RED SEA — i.e. by the route which they had taken on leaving Egypt which is at the south-west corner. From there (where they were at that moment) they went towards the east.
Siftei Chakhamim
Had they not sinned, etc. Meaning: Due to their sin, Hashem did not manipulate the King of Edom’s heart to allow them to pass through his land.
Rav Hirsch on Torah
Kap. 2. V. 1. ונפן וגו׳ (siehe zum vorigen Verse). ימים רבים, ebenfalls neunzehn Jahre nach סדר עולם (daselbst) י׳׳ט שנה היו חוזרין ומטורפין.