Charles Ellicott Commentary Numbers 31:49

"and they said unto Moses, Thy servants have taken the sum of the men of war that are under our charge, and there lacketh not one man of us." — Numbers 31:49 (ASV)

There lacketh not one man of us.— It is obvious from the smallness of the number of the Israelite warriors, as well as from the reference to those chiefs only of the Midianites who were the vassals of Sihon, and from the strength of the Midianite nation in the time of Gideon (Judges 6-8), that the attack was made only upon that particular portion of the nation which had been concerned in the seduction of the Israelites to the worship of Baal Peor. The Midianites were probably attacked in an unprepared and defenceless state.

After due allowance, however, has been made for all these circumstances, the fact that not a single Israelite warrior perished can be satisfactorily explained only on the supposition that God graciously granted His people miraculous aid and protection.