صحيح البخاري

Narrated Al-Ju'aid bin `Abdur Rahman:

I saw As-Sa'ib bin Yazid when he was ninety-four years old, quite strong and of straight figure. He said, "I know that I enjoyed my hearing and seeing powers only because of the invocation of Allah's Apostle . My aunt took me to him and said, 'O Allah's Messenger! My nephew is sick; will you invoke Allah for him?' So he invoked (Allah) for me."