Musnad Ahmad 1153:1608

'Abd al-Razzaq narrated to us, from Ma'mar, al-Zuhri said: 'Urwah ibn al-Zubayr informed me that 'A'ishah said: "I never knew my parents except while they were practicing the religion. Not a day passed us by except that the Messenger of Allah (peace and blessings of Allah be upon him) would come to us at both ends of the day, morning and evening. When the Muslims were afflicted, Abu Bakr went out as an emigrant toward the land of Abyssinia. When he reached Bark al-Ghimad, Ibn al-Dughunnah—who was the leader of the Qarah—met him and said: 'Where do you intend to go, O Abu Bakr?' Abu Bakr said: 'My people have expelled me,' and he mentioned the hadith. The Messenger of Allah (peace and blessings of Allah be upon him) said to the Muslims: 'I have been shown the place of your emigration; I was shown a salt-marsh with date palms between two lava fields'—and those are two rocky tracts. So, those who had emigrated to Medina left when the Messenger of Allah (peace and blessings of Allah be upon him) mentioned it, and some of the Muslims who had emigrated to the land of Abyssinia returned to Medina. Abu Bakr prepared to emigrate, but the Messenger of Allah (peace and blessings of Allah be upon him) said to him: 'Wait, for I hope that permission will be granted to me.' Abu Bakr said: 'Do you hope for that, may my father and mother be sacrificed for you?' He said: 'Yes.' So Abu Bakr kept himself for the Messenger of Allah (peace and blessings of Allah be upon him) to accompany him, and he fed two she-camels he had with the leaves of the samur tree for four months." Al-Zuhri said: 'Urwah said: 'A'ishah said: "While we were sitting in our house one day at the height of noon, someone said to Abu Bakr: 'This is the Messenger of Allah (peace and blessings of Allah be upon him) approaching, covered, at an hour he would not usually come to us.' Abu Bakr said: 'May my father and mother be sacrificed for him, if he has come at this hour, it is for a matter.' The Messenger of Allah (peace and blessings of Allah be upon him) came, asked for permission, was granted it, and entered. When the Messenger of Allah (peace and blessings of Allah be upon him) entered, he said to Abu Bakr: 'Ask those who are with you to leave.' Abu Bakr said: 'They are only your family, may my father and mother be sacrificed for you, O Messenger of Allah.' The Prophet (peace and blessings of Allah be upon him) said: 'For I have been granted permission to leave.' Abu Bakr said: 'The companionship, may my father be sacrificed for you, O Messenger of Allah?' The Messenger of Allah (peace and blessings of Allah be upon him) said: 'Yes.' Abu Bakr said: 'Then take, may my father be sacrificed for you, O Messenger of Allah, one of these two she-camels of mine.' The Messenger of Allah (peace and blessings of Allah be upon him) said: 'For the price.' She said: So we prepared them with the swiftest preparation, and we made them a travel meal in a leather bag. Asma' bint Abi Bakr cut a piece from her belt and tied the bag with it; that is why she was called 'Dhat al-Nitaqayn' (The One with the Two Belts). Then the Messenger of Allah (peace and blessings of Allah be upon him) and Abu Bakr reached a cave in a mountain called Thawr, and they stayed in it for three nights."