The Apostle Paul was perhaps the greatest intellectual in Church History.  He was a man of great pedigree.  He was trained as a legal scholar and philosopher.  He was also a rabid enemy of the Faith until he was transformed by the Grace of God.  Paul was changed by God's amazing Grace, and he he never forgot it.  He lived his life as one who was deeply devoted to the living Jesus.  One of his greatest personal enemies was pride.  God's gave him intrinsic memorials in his body so that Paul would remember that he depended on the all sufficiency of Grace.