1 Samuel 17:26-37 ESV
And David said to the men who stood by him, “What shall be done for the man who kills this Philistine and takes away the reproach from Israel? For who is this uncircumcised Philistine, that he should defy the armies of the living God?” And the people answered him in the same way, “So shall it be done to the man who kills him.”
Now Eliab his eldest brother heard when he spoke to the men. And Eliab’s anger was kindled against David, and he said, “Why have you come down? And with whom have you left those few sheep in the wilderness? I know your presumption and the evil of your heart, for you have come down to see the battle.” And David said, “What have I done now? Was it not but a word?” And he turned away from him toward another, and spoke in the same way, and the people answered him again as before.
When the words that David spoke were heard, they repeated them before Saul, and he sent for him. And David said to Saul, “Let no man’s heart fail because of him. Your servant will go and fight with this Philistine.” And Saul said to David, “You are not able to go against this Philistine to fight with him, for you are but a youth, and he has been a man of war from his youth.” But David said to Saul, “Your servant used to keep sheep for his father. And when there came a lion, or a bear, and took a lamb from the flock, I went after him and struck him and delivered it out of his mouth. And if he arose against me, I caught him by his beard and struck him and killed him. Your servant has struck down both lions and bears, and this uncircumcised Philistine shall be like one of them, for he has defied the armies of the living God.” And David said, “The LORD who delivered me from the paw of the lion and from the paw of the bear will deliver me from the hand of this Philistine.” And Saul said to David, “Go, and the LORD be with you!”
ESV: English Standard Version 2016