1 Samuel 13:8-14
8 Saul waited for Samuel for seven days, the amount of time he had been told by Samuel to wait. But the prophet did not come to Gilgal, and the people began to slip away. A few more days and Saul would have no army left, so he decided to take matters into his own hands.
Saul: 9 Bring me the animals for burnt offerings and the offerings of peace for the Lord.
10 Although Saul was not a priest, he offered the burnt offering himself without waiting for Samuel. Immediately after Saul finished the offering, when the aroma of the sacrifice lingered over the land, Samuel arrived, and Saul went out to greet him and to pay his respects. But Samuel knew Saul had overstepped his bounds.
Samuel: 11 What have you done?
Saul: The people were deserting me! You didn’t come when you promised, and the Philistines were gathering for war at Michmash. 12 I thought, “The Philistines are going to attack me here in Gilgal, and I haven’t even asked the Eternal One to favor us.” So I took matters into my own hands—I didn’t want to—but I offered the burnt offering myself.
Samuel: 13 That was a foolish thing, Saul. You have not kept the commandment that the Eternal, your True God, gave to you. He was willing to establish your kingdom over Israel for all time, 14 but now your kingdom, your dynasty, will not last. He has found a man who seeks His will and has appointed him king over all the people instead of you because you have not kept to what the Eternal One commanded.