Jamieson, Fausset and Brown on Genesis 14:15-16

15-16. he divided himself ... by night--This war between the petty princes of ancient Canaan is exactly the same as the frays and skirmishes between Arab chiefs in the present day. When a defeated party resolves to pursue the enemy, they wait till they are fast asleep; then, as they have no idea of posting sentinels, they rush upon them from different directions, strike down the tent poles--if there is any fight at all, it is the fray of a tumultuous mob--a panic commonly ensues, and the whole contest is ended with little or no loss on either side.