Saul was the first king of Israel.  He was chosen by the people as their king and not by God.  Please remember that at this time in the history of Israel the people were living outside of the will of God.  Spiritual carnality was rampant.  The people wanted a king so that they could be like the other city-states in the promised land.  They chose a man who reflected who they were inside of their hearts.  Saul was a man who would rather serve himself that serve the living God.