This day will Yahweh deliver you into my hand; and I will strike you, and take your head from off you; and I will give the dead bodies of the host of the Philistines this day to the birds of the sky, and to the wild animals of the earth; that all the earth may know that there is a God in Israel,
And so David's brother Eliab saw David's interest in this thing, and he said to David, "Who's watching over your sheep back there in the wilderness kid? You better get on home in a hurry. I know your heart, you're just-dad probably didn't send you down here. You're just down to see what a war looks like and you go home in a hurry." His big brother is trying to sort of protect him.