Rashi on Deuteronomy 1:7/רש"י על דברים א׳:ז׳

1פנו וסעו לכם TURN YOU AND JOURNEY — this was the journey to Arad and Hormah mentioned in Numbers 21:1—3.

2ובאו הר האמרי — Understand this according to what it literally implies.

3ואל כל שכניו AND TO ALL ITS NEIGHBOURING PLACES — Ammon, and Moab, and Mount Seir.

4בערבה IN THE PLAIN — this is the plain of the forest.

5בהר IN THE MOUNTAIN — this is the King’s mountain.

6ובשפלה AND IN THE LOW LAND — this is the low land of the south country.

7ובנגב ובחוף הים AND IN THE SOUTH COUNTRY AND BY THE SEA COAST — Ashkelon and Gaza and Caesarea, etc., all as is stated in Sifrei Devarim 6:1.

8עד הנהר הגדל TO THE GREAT RIVER [THE RIVER EUPHRATES] — Because it is mentioned in connection with the Land of Israel, it terms it "great". A popular proverb says: A king’s servant is a king, attach yourself to a captain and people will bow down to you; go near to an anointed (a distinguished) person and you become anointed (distinguished) yourself (cf. Rashi on Shevuot 47b and Genesis 15:18).