Why did David pick up five stones to fight Goliath?

David only needed one shot to take down the giant known as Goliath, yet he picked up 5 stones in preparing for battle (1 Samuel 17:40).  While David trusted in God and knew that God would grant him the victory, he also knew to be prepared.  He needed to make sure he had enough sling stones to hurl just in case the giant did not go down.  Being prepared is not doubting God’s ability, it is showing that you trust God to deliver on His promises.  Even though we have faith in God’s ability, we are required to do our part and be ready for anything that may come our way.