David was so successful because there was a war a long time ago there was a guy taht was 10 feet tall and no one was able to beat him, even with everyone goig against him no one could beat him.
David was a brother of 12 and none of them liked him because was no help and he was the smallest. But then one day David had hope and he knew that Jesus was with him and he knew no matter what everything as in Jesus's hands.
David went out to war with just a sling shot and 3 pebbles. he shot the first on and missed him, then he went for the 2nd time and missed again. he only had one left.
David was an Israelite king and the first monarch of all the Israelite tribes. David was also important to Judaism, Christianity, and Islam.