From a human perspective, Saul broke off his pursuit because he did not know for sure that David was trapped and close to being caught. If he did, then he would have likely waited to catch David before going off to fight the Philistines. In his providence, however, the Lord caused the Philistines to attack Israel and made sure that the messenger arrived at the most opportune moment.1
27 lorsqu'un messager vint dire à Saül: Hâte-toi de venir, car les Philistins ont fait invasion dans le pays.