Those words were written for the haggatonsof society, for misfits and outcasts. God uses them all.
Moses ran from justice, but God used him. Jonah ran from God, but God used him. Rahab ran a brothel, Samson ran to the wrong woman, Jacob ran in circles, Elijah ran into the mountains, Sarah ran out of hope, Lotran with the wrong crowd, but God used them all.
And David? God saw a teenage boy serving him in the backwoods of Bethlehem, at the intersection of boredom and anonymity, and through the voice of a brother, God called, “David! Come in. Someone wants to see you.” Human eyes saw a gangly teenager enter the house, smelling like sheep and looking like he needed a bath. Yet, “the Lord said, ‘Arise, anoint him; for this is the one!’” (1 Samuel 16:12)
God saw what no one else saw: a God-seeking heart. David, for all his foibles, sought God like a lark seeks sunrise. He took after God’s heart, because he stayed after God’s heart. In the end, that is all God wanted or needed…wants or needs. Others measure your waist size or wallet. Not God. He examines hearts. When He finds one set on Him, He calls it and claims it.
— Max Lucado in Facing Your Giants