They had to be listening closely, attentively, totally focused on Him to recognize His sound.
Throughout Scripture there are so many accounts where His ways of war seem so far out there. So impossible that the only way winning was possible, was only because of Him.
Trust. Faith. Focus.
He is in control. We must stand at the ready "in" Him.
“Listen for a sound like shuffling feet."
"God will be two steps ahead of you"