Moreover David said, "the Lord, who delivered me from the paw of the lion and from the paw of the bear, He will deliver me from the hand of this Philistine." (1 Samuel 17:37)
For the most part, great heroic deeds follow heroic character. Just as big endeavors usually follow smaller ones. It is a matter of being faithful in the little issues of life before attempting the greater ventures. Jesus explained it this way, "He who is faithful in what is least is faithful also in much; and he who is unjust in what is least is unjust also in much." David's deeds and fame were by all means progressive. I am sure that before he killed the lion and the bear he drove off the fox. And before that he carefully watched and obeyed his father's direction. These things he did without fanfare. These things he did from character. He did not seek greatness; greatness sought him. Remember, when Samuel came to anoint a new king from David's family, David was doing what he was called to do at the time, tend sheep.