1 Samuel 17:12-37 KJV
Now David was the son of that Ephrathite of Beth-lehem-judah, whose name was Jesse; and he had eight sons: and the man went among men for an old man in the days of Saul. And the three eldest sons of Jesse went and followed Saul to the battle: and the names of his three sons that went to the battle were Eliab the firstborn, and next unto him Abinadab, and the third Shammah. And David was the youngest: and the three eldest followed Saul. But David went and returned from Saul to feed his father's sheep at Beth-lehem. And the Philistine drew near morning and evening, and presented himself forty days.
And Jesse said unto David his son, Take now for thy brethren an ephah of this parched corn, and these ten loaves, and run to the camp to thy brethren; and carry these ten cheeses unto the captain of their thousand, and look how thy brethren fare, and take their pledge. Now Saul, and they, and all the men of Israel, were in the valley of Elah, fighting with the Philistines.
And David rose up early in the morning, and left the sheep with a keeper, and took, and went, as Jesse had commanded him; and he came to the trench, as the host was going forth to the fight, and shouted for the battle. For Israel and the Philistines had put the battle in array, army against army. And David left his carriage in the hand of the keeper of the carriage, and ran into the army, and came and saluted his brethren. And as he talked with them, behold, there came up the champion, the Philistine of Gath, Goliath by name, out of the armies of the Philistines, and spake according to the same words: and David heard them. And all the men of Israel, when they saw the man, fled from him, and were sore afraid. And the men of Israel said, Have ye seen this man that is come up? surely to defy Israel is he come up: and it shall be, that the man who killeth him, the king will enrich him with great riches, and will give him his daughter, and make his father's house free in Israel. And David spake to the men that stood by him, saying, What shall be done to the man that killeth this Philistine, and taketh 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 after this manner, saying, So shall it be done to the man that killeth him.
And Eliab his eldest brother heard when he spake unto the men; and Eliab's anger was kindled against David, and he said, Why camest thou down hither? and with whom hast thou left those few sheep in the wilderness? I know thy pride, and the naughtiness of thine heart; for thou art come down that thou mightest see the battle. And David said, What have I now done? Is there not a cause? And he turned from him toward another, and spake after the same manner: and the people answered him again after the former manner.
And when the words were heard which David spake, they rehearsed them before Saul: and he sent for him. And David said to Saul, Let no man's heart fail because of him; thy servant will go and fight with this Philistine. And Saul said to David, Thou art not able to go against this Philistine to fight with him: for thou art but a youth, and he a man of war from his youth. And David said unto Saul, Thy servant kept his father's sheep, and there came a lion, and a bear, and took a lamb out of the flock: and I went out after him, and smote him, and delivered it out of his mouth: and when he arose against me, I caught him by his beard, and smote him, and slew him. Thy servant slew both the lion and the bear: and this uncircumcised Philistine shall be as one of them, seeing he hath defied the armies of the living God. David said moreover, The LORD that delivered me out of the paw of the lion, and out of the paw of the bear, he will deliver me out of the hand of this Philistine. And Saul said unto David, Go, and the LORD be with thee.