What does 1 Samuel 15:13 mean?
The prophet Samuel has been looking for Saul to confront him. Saul has disobeyed God's command to utterly wipe out all the people and animals of the Amalekites (1 Samuel 15:3, 9). Now Samuel catches up to Saul at Gilgal. This seems appropriate since it is where Saul was finally and openly declared the king (1 Samuel 11:14–15) and where the rejection of his kingdom was announced following his previous disobedience of the Lord (1 Samuel 13:7–15).Saul greets Samuel and immediately begins to lie to the prophet or, perhaps, to reveal that he has been lying to himself. Saul's greeting is the standard among the Israelites: "Blessed be you to the LORD." Then Saul adds that he has performed the commandment of the Lord.
Since the Lord's command was for Saul to kill every living thing among the Amalekites (1 Samuel 15:3) and since he obviously did not do so (1 Samuel 15:9), Saul's blunt claim that he obeyed God seems all the more foolish.