David was successful because al long time in the bible there was a war going on and one of the guys on the other side was 10 feet tall and no one could beat him. David was a brother of 12 and he was the smallest out of all of them and now one liked him.
All of his brothers were big tall and strong and he was just the little one. One day David was like I feel like jesus is with me and he loves me and he has my back and so he went out to the war and he only had a sling shot and three rocks.
He took the frist rock shot it ans missed... he got the other one and missed again... his final one he started swinging it arond his head and no one was talking ... no sounds from miles away. the only noise you heard was the wind.
David was scared but he knew that God was with him. he shot the rock and it went right in to the middle of the 10 foot guys head and he fell and died and everyone stared yelling and they were very happy