In light of the fact that the Philistines were not fully conquered in Saul’s lifetime (see 1 Samuel 31:1–13), the statement made in these verses should be understood as a reference to potential. Saul would have the potential to deliver the Israelites from the Philistines if he led the people in covenant faithfulness and obedience to the Lord.1 The timing and manner of deliverance was subsequently modified on account of Saul’s failure to carry out the responsibilities that were placed upon him.2
15 Now the day before Saul came, the LORD had revealed to Samuel: