1 Samuel 26:2 - Ellicott's Commentary On The Whole Bible

Then Saul arose, and went down to the wilderness of Ziph. — We assume, then, that after the marriage of David with Abigail he and his armed band returned again to his old neighbourhood in the south — in the desert of Judah — the district named after the Hill of Hachilah being, no doubt, in all respects well adapted for the permanent encampment of such a large band as David’s now most certainly was. David, who had been forced on a previous occasion to leave it on account of the hot pursuit of Saul, aided by the Ziphites, who knew the country and its resources so well, probably now supposed, after the protestation of Saul at En-gedi, that he would now at least be left in peace. But he forgot with whom he had to do — forgot the state of mind of his determined foe, and how likely it was that the old mania would return with redoubled force. The Ziphites, however, who knew Saul, and the feeling respecting David which existed at the court of Saul, repeated their old tactics, and sent, as on a previous occasion, to suggest that with their help the obnoxious chieftain and his free lances could be destroyed. The temptation was too great to be resisted; so probably, with the advice of Abner, Saul took the field again. The 3,000 seem to have been the standing force which Saul kept round him in the Gibeah garrison. (See the first notice of this standing army in 1 Samuel 13:2.)