What do we learn from the fact that the Torah writes "Lo Yisyatzev Ish bi'Feneichem" - and not "Ish Lo Yisyatzev bi'Feneichem"?:
Rashi: It teaches us that not only a man will be unable to stand against us, but even a nation, a family (tribe) or a woman using witchcraft. 1
Rashi: And the Torah adds "Ish" to include even a man like Og Melech ha'Bashan.
Where does the promise "Lo Yisyatzev Ish" apply?
Rashbam: It refers specifically to within the defined borders.
Seforno: It applies with whoever they fight, even in Chutz la'Aretz.
When did Hashem issue such a promise?
Rashi: In Mishpatim Sh?mos, 23:27, when He said "Es Eimasi Ashalach Lefanecha ... Venasati es Kol Oyvecha Elecha Oref".