1 Samuel 30:9

So David went, he and the six hundred men that were with him, and came to the brook Besor, where those that were left behind stayed.

Came to the brook Besor - supposed to be Wady Sheriah, the deep bed of a winter torrent, which is distantly traceable from the adjoining heights, in its sinuous course up to its source, far away in the distant hills of Judah. It is about 30 yards in width, and is flanked on both sides by a range of steep precipitous banks, pouring in the raining season a copious volume of muddy water to the sea; but with the return of spring this full current dwindles down to a few stagnant pools, and the wady becomes entirely dry. The verdant bank of a stream naturally offend a convenient rest to the solders, who, through fatigue, were unable to continue the pursuit. But the torrent was probably full, and from the impetuosity of its swollen current difficult to be forded, so that 200 of the men, faint and exhausted with the previous forced and long-continued pursuit, declared their total inability to proceed any further, and sank down on the grass. This was a new trial to the faith of David, to pursue the enemy with the diminution of his little army by one-third. But as the occasion demanded energy and despatch, he determined to advance as rapidly as possible with his reduced forces, relying on the encouraging oracle of the Lord.