“I had a son who had bladder (kidney) stone and it was said to me that it has no medicine except operating and I operated, then the child died. The Shi’ah said, ‘You have caused the death of your son. I then wrote to abu al-Hassan al-‘Askariy (a.s.). He (the Imam) signed the answer that said, ‘O Ahmad, you are not responsible for what you have done. You tried to cure him and his death (the appointed time) was in what you did.”’