John Calvin on Isaiah 41:3

3. He pursued them. The Prophet again commends, by the greatness of the victory, the extraordinary kindness of God. It is of the highest importance that he obtained it in a country which was unknown to him; for it is difficult and hazardous to pursue enemies in unknown countries; and how great is the value of a knowledge of places is plainly shewn by history, and daily experienced by those who carry on war. That was no obstacle to Abraham; and hence it is still more evident, that he was led and assisted by the hand of God to conduct his followers courageously.