Comentario sobre Deuteronómio 20:4

כי ה׳ אלהיכם וגו׳ FOR THE LORD YOUR GOD [IS HE WHO GOETH WITH YOU] — They come to war relying on the conquering strength of human beings (lit., flesh and blood) but you come relying on the strength of the Omnipresent God! The Philistines once came to war relying on the strength of Goliath — what was his end? He fell and they fell with him (Sotah 42a).

כי ה' אלוקיכם ההולך עמכם, “for the Lord your G’d is the One going with you.” The details about who is subject to the draft are meant to remind us that in spite of our feeling physically superior to our enemies, success in war, as in other enterprises that are facing opposition, depends on G’d’s being on our side. If He is, we will win, if not, our numerical superiority or our superior weaponry will not secure us victory either.

להושיע אתכם, “to save you.” This promise refers to total salvation, i.e. that the Israelites would not suffer casualties in their war of conquest against the seven Canaanite nations. It will be just like the punitive campaign against Midian when not a single Israelite soldier was even hurt (Numbers 31,49). It is customary that even victorious armies sustain many casualtis in battle. A war fought as a divine commandment is one when the people carrying out the commandments will prove immune. This is why Joshua was so upset when in the first battle of Ai his army sustained 36 casualties (Joshua 7,5-7). Actually, according to a commentary in Sanhedrin 44, the “36” casualties were merely a single soldier named Yair ben Menashe, who was such an outstanding person that he was considered as equivalent to 36 members of the 71-member Sanhedrin.