He waited seven days, the time appointed by Samuel; but Samuel did not come to Gilgal, and the people began to slip away from Saul.
References for 1 Samuel 13:8
So Saul said, "Bring the burnt offering here to me, and the offerings of well-being." And he offered the burnt offering.
As soon as he had finished offering the burnt offering, Samuel arrived; and Saul went out to meet him and salute him.
Samuel said, "What have you done?" Saul replied, "When I saw that the people were slipping away from me, and that you did not come within the days appointed, and that the Philistines were mustering at Michmash,
I said, "Now the Philistines will come down upon me at Gilgal, and I have not entreated the favor of the Lord'; so I forced myself, and offered the burnt offering."
Samuel said to Saul, "You have done foolishly; you have not kept the commandment of the Lord your God, which he commanded you. The Lord would have established your kingdom over Israel forever,
but now your kingdom will not continue; the Lord has sought out a man after his own heart; and the Lord has appointed him to be ruler over his people, because you have not kept what the Lord commanded you."
And Samuel left and went on his way from Gilgal. The rest of the people followed Saul to join the army; they went up from Gilgal toward Gibeah of Benjamin. Saul counted the people who were present with him, about six hundred men.
References for 1 Samuel 13:15
Saul, his son Jonathan, and the people who were present with them stayed in Geba of Benjamin; but the Philistines encamped at Michmash.
And raiders came out of the camp of the Philistines in three companies; one company turned toward Ophrah, to the land of Shual,
another company turned toward Beth-horon, and another company turned toward the mountain that looks down upon the valley of Zeboim toward the wilderness.
References for 1 Samuel 13:18