Musannaf Ibn Abi Shayba 36:505

Husayn ibn Ali narrated to us, from Za'idah, from Musa ibn Abi 'Aishah, he said: Ubaydullah ibn Abdullah ibn Utbah narrated to me, he said: I came to Aisha and said: "Tell me about the illness of the Messenger of Allah, may Allah bless him and grant him peace." She said: "Yes. The Messenger of Allah, may Allah bless him and grant him peace, became ill and grew heavy, then he fainted. Then he recovered and said: 'Place water for me in the washbasin.' So we did. She said: 'Then he performed ghusl, then he went to stand up, but he fainted. Then he recovered and said: 'Place water for me in the washbasin.' So we did. She said: 'Then he performed ghusl, then he went to stand up, but he fainted.' She said: 'Then he recovered and said: 'Place water for me in the washbasin.' I said: 'We have already done so.' She said: 'Then he performed ghusl, then he went to stand up, but he fainted. Then he recovered and said: 'Have the people prayed yet?' We said: 'No, O Messenger of Allah, they are waiting for you.' She said: 'And the people were staying in the mosque, waiting for the Messenger of Allah, may Allah bless him and grant him peace, to lead them in the late night prayer (Isha).' She said: 'Then the Messenger of Allah, may Allah bless him and grant him peace, performed ghusl, then he went to stand up, but he fainted. Then he recovered and said: 'Have the people prayed yet?' I said: 'No.' So the Messenger of Allah, may Allah bless him and grant him peace, sent word to Abu Bakr to lead the people in prayer.' She said: 'The messenger came to him and said: 'The Messenger of Allah, may Allah bless him and grant him peace, commands you to lead the people in prayer.' He said: 'O Umar, lead the people in prayer.' He said: 'You are more entitled to it; the Messenger of Allah, may Allah bless him and grant him peace, only sent word to you.' She said: 'So Abu Bakr led them in prayer during those days. Then the Messenger of Allah, may Allah bless him and grant him peace, felt a lightness in himself, so he went out for the Dhuhr prayer, between al-Abbas and another man. He said to them: 'Seat me on his right.' When Abu Bakr heard his movement, he went to step back, but he (the Prophet) ordered him to remain in his place.' She said: 'So they seated him on his right, and Abu Bakr was praying following the prayer of the Messenger of Allah, may Allah bless him and grant him peace, while he (the Prophet) was sitting, and the people were praying following the prayer of Abu Bakr.' He (the narrator) said: 'So I came to Ibn Abbas and said: 'Shall I present to you what Aisha narrated to me?' He said: 'Bring it.' So I presented this to him, and he did not deny any of it, except that he said: 'Did she tell you who the other man was?' I said: 'No.' He said: 'He was Ali, may Allah have mercy on him.'"