פירוש על יהושע 1:3

Every place upon which the sole of your feet will tread. This is similar to what was said to Moshe. Regarding this, we learned in the Sifre. ‘If [this verse] is to teach us about the boundaries of Eretz Yisroel, the Torah has already stated:⁹Devorim 11:24. From the wilderness and the Lebanon etc.¹⁰Therefore we know the boundaries of Eretz Yisroel from the Torah. If so, why is it said here: Every place upon which the sole will tread? This includes the lands outside Eretz Yisroel. After you have conquered the land, everything you conquer outside the land will be sacred and will belong to you.’

This is a reference to the beginning of the Story.