Charles Ellicott Commentary 1 Samuel 26:2

"Then Saul arose, and went down to the wilderness of Ziph, having three thousand chosen men of Israel with him, to seek David in the wilderness of Ziph." — 1 Samuel 26:2 (ASV)

Then Saul arose, and went down to the wilderness of Ziph. — We assume, then, that after David’s marriage to Abigail, he and his armed band returned to his old neighborhood in the south, in the desert of Judah. The district named after the Hill of Hachilah was, no doubt, in every respect well-suited for the permanent encampment of such a large band as David's had now certainly become.

David had been forced to leave this area on a previous occasion because of Saul's hot pursuit, aided by the Ziphites who knew the country and its resources so well. He probably now supposed, after Saul's solemn promise at En-gedi, that he would, at least, be left in peace.

But David forgot who he was dealing with—he 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 attitude toward David that existed at Saul's court, repeated their old tactics and sent word, as on a previous occasion, suggesting that with their help the obnoxious chieftain and his free lances could be destroyed.

The temptation was too great for Saul to resist, so, probably with Abner's advice, Saul took the field again. The 3,000 men seem to have been the standing force Saul kept around him in the Gibeah garrison (see the first notice of this standing army in 1 Samuel 13:2).