My ClassMate Told me that he has exchanged my papers with his in Board Exams. He Swear That He Had Done this. Again He Said You will get Grade C, he again swear. When I asked My Teacher Is It Possible, He said that it is not possible and Said he is gesturing me to say Yes. Finally He said he is Joking. So I should Believe Him That he was Joking or keep in mind that he swear. What Quran Say about these kind of people?