Albert Barnes Commentary Judges 7:11

"and thou shalt hear what they say; and afterward shall thy hands be strengthened to go down into the camp. Then went he down with Purah his servant unto the outermost part of the armed men that were in the camp." — Judges 7:11 (ASV)

The armed men - The word is rendered harnessed in Exodus 13:18 (see the note). The most probable meaning of the word is arrayed in divisions or ranks.