1 Samuel 17:30

The people answered him in this way, saying, “So shall it be done to the man who kills him.”

Eliab his oldest brother heard when he spoke to the men; and Eliab’s anger burned against David, and he said, “Why have you come down? With whom have you left those few sheep in the wilderness? I know your pride and the evil of your heart; for you have come down that you might see the battle.”

David said, “What have I now done? Is there not a cause?”

When the words were heard which David spoke, they rehearsed them before Saul; and he sent for him.

David said to Saul, “Let no man’s heart fail because of him. Your servant will go and fight with this Philistine.”

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 a man of war from his youth.”