Charles Ellicott Commentary 1 Samuel 26:3

"And Saul encamped in the hill of Hachilah, which is before the desert, by the way. But David abode in the wilderness, and he saw that Saul came after him into the wilderness." — 1 Samuel 26:3 (ASV)

But David remained in the wilderness. —The former incident, when David spared Saul’s life, happened long after the information from the Ziphites brought the king to the hill “Hachilah, on the south of Jeshimon.” Then David, on hearing of the march of Saul and his army, retreated into the wilderness of Maon. Saul pursued him, and David and his force were then only saved from destruction because of the news of a formidable Philistine invasion. This intelligence called Saul’s forces away from the pursuit of David. David, unmolested, withdrew his band and sought refuge at En-gedi (1 Samuel 23).

After the Philistine invasion had been repulsed, Saul again resumed operations against David and marched his force to En-gedi. In one of its caves, the event occurred where David for the first time spared the king’s life (1 Samuel 24). Now, after the information from the Ziphites had brought down Saul and his soldiers from Gibeah, David does not flee in haste to Maon, and from there to En-gedi, nor is Saul called away by any Philistine invasion; but David remains in the wilderness, and his scouts come and tell him that Saul in very deed (1 Samuel 26:4) was come after him in force.