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.

Cross-reference

In 1 Samuel 23:23-25, Saul previously pursued David in the same wilderness of Ziph, showing this is a repeated pattern of pursuit.

In 1 Samuel 24:2, Saul also takes 3000 chosen men to seek David, nearly identical wording to this verse.