As in 1 Samuel 23:19–20, the Ziphites saw an opportunity to earn Saul’s favour. Revealing David’s location they probably expected to receive some kind of reward,1 or at the very least prevent any retribution from an angry king (see 1 Samuel 22:1–23).
1 Then the Ziphites came to Saul at Gibeah, saying, “Is not David hiding himself on the hill of Hachilah, which is on the east of Jeshimon?”