" The messenger of Allah said: 'Shall I not tell you of the biggest of the major sins?' they said : 'Of course! O Messenger of Allah!' He said: 'To join partners with Allah, and disobeying one's parents.'"He said : " He sat up, and he had been reclining. He said: 'And false testimony, or false speech.' And the Messenger of Allah would not stop saying it until we said (to ourselves): 'I wish that he would stop.'"