John Gill Commentary Deuteronomy 1:30

"Jehovah your God who goeth before you, he will fight for you, according to all that he did for you in Egypt before your eyes," — Deuteronomy 1:30 (ASV)

The Lord your God, which goes before you
In a pillar of cloud by day, and in a pillar of fire by night:

he shall fight for you ;
therefore, though their enemies were greater and taller than they, yet their God was higher than the highest; and cities walled up to heaven would signify nothing to him, whose throne is in the heavens:

according to all that he did for you in Egypt before your eyes :
which is observed to encourage their faith in God; for he that wrought such wonders in Egypt for them, which their eyes, at least some of them, and their fathers, however, had seen, what is it he cannot do?