What did the Prophet Muhammad (saw) inform the family of Abu Bakr (peace be upon him) he had been given permission to do when he visited them at an unexpected time?
 Narrated `Aisha:                     (the wife of the Prophet) "I do not remember my parents believing in any religion other than the Religion (of Islam), and our being visited by Allah's Apostle in the morning and in the evening. One day, while we were sitting in the house of Abu Bakr (my father) at noon, someone said, 'This is Allah's Apostle coming at an hour at which he never used to visit us.' Abu Bakr said, 'There must be something very urgent that has brought him at this hour.' The Prophet said, 'I have been allowed to go out (of Mecca) to migrate.' "