By lot - To determine who should go up first Judges 20:18. The shape of the ground probably made it impossible for the whole force to operate at once; and the question of spoil would have something to do with the arrangement. (Compare 1 Samuel 30:22-25.)
Related Commentaries of Judges 20:9
Judges 20:9
9 But now this shall be the thing which we will do to Gibeah; we will go up by lot against it;