1 Samuel 26:3

And Saul pitched in the hill of Hachilah, which [is] before
Jeshimon, by the way
To the wilderness; the very same place where the Ziphites suggested David was:

but David abode in the wilderness;
not in the hill of Hachilah, but in the wilderness of Ziph itself:

and he saw that Saul came after him into the wilderness;
he understood, by some information he had, that Saul had set out from Gibeah, and was coming to seek for him in the wilderness of Ziph; perhaps Jonathan had given him intelligence; however, he was not quite certain, as appears by what follows.