And Samuel said to Saul, Thou hast done foolishly: thou hast not kept the commandment of the LORD thy God, which he commanded thee: for now would the LORD have established thy kingdom upon Israel for ever.
And Samuel said to Saul, "You have done foolishly. You have not kept the command of the LORD your God, with which he commanded you. For then the LORD would have established your kingdom over Israel forever.
"That was a fool thing to do," Samuel said to Saul. "If you had kept the appointment that your God commanded, by now God would have set a firm and lasting foundation under your kingly rule over Israel.
Samuel said to Saul, "You have been foolish. You have not kept the command which the Lord your God gave you. It was at this time that the Lord would have permanently established your reign over Israel,
1 Samuel 13:13 In-Context
“What have you done?” asked Samuel. Saul replied, “When I saw that the men were scattering, and that you did not come at the set time, and that the Philistines were assembling at Mikmash,
I thought, ‘Now the Philistines will come down against me at Gilgal, and I have not sought the LORD’s favor.’ So I felt compelled to offer the burnt offering.”
“You have done a foolish thing,” Samuel said. “You have not kept the command the LORD your God gave you; if you had, he would have established your kingdom over Israel for all time.
But now your kingdom will not endure; the LORD has sought out a man after his own heart and appointed him ruler of his people, because you have not kept the LORD’s command.”
Then Samuel left Gilgal and went up to Gibeah in Benjamin, and Saul counted the men who were with him. They numbered about six hundred.