Charles Ellicott Commentary 1 Samuel 26:13

"Then David went over to the other side, and stood on the top of the mountain afar off; a great space being between them;" — 1 Samuel 26:13 (ASV)

David went over to the other side.—That is to say, after taking the royal spear and flask of water from beside the sleeping king, David with Abishai left Saul's camp. Then, crossing the deep ravine, they re-ascended the opposite hill or mountain—a deep gorge then lay between him and the camp—and uttered his shrill cry, which awoke the sleeping sentinel, who seems to have immediately roused Abner.

Keil calls attention here to the special notice in the text that the mountain from where David spoke was far off—not, as we might say, “as the crow flies,” but far off because a deep, steep ravine lay between Saul's camp and the hill on which David and Abishai stood.

“On the previous occasion when, in the cave of En-gedi, the son of Jesse cut off the skirt of the royal garment, David fearlessly cried to Saul when the king was still evidently quite close to the cave. Now, however, he seems to have counted far less on any change in Saul’s mind than he had done before ... in fact, he rather feared lest Saul should endeavor to get him into his power as soon as he woke from his sleep.”