The wise elderly John wrote this brief letter towards the end of the first century.  John sent this letter to a man named Gaius.  Gaius often showed hospitality to traveling teachers & missionaries.  While John praised his genourosity, he also warned him against a man who was refusing to listen to spiritual leaders in authority.  This is a very personal letter and still carries the same theme of truth from the second letter.  Truth & love must be tempered with wisdom.