Imām Bukhārī narrates: 'Umar ibn Hafs ibn Ghiyāth narrated to us, he said: My father narrated to me, he said: Al-A'mash narrated to us, from Ibrāhīm, al-Aswad said:

We were with 'Ā'ishah, may Allāh be pleased with her, so we mentioned steadfastness in prayer and its greatness. 'Ā'ishah narrated: When the Messenger of Allāh ﷺ became afflicted with the illness in which he passed away, the time of prayer came and its adhān was given. So he said: Command Abū Bakr to lead the people in prayer. It was said to him: Abū Bakr is very tender-hearted; when he stands in your place, he will not be able to lead the people in prayer. And he said it again; the family said the same thing again. Then he said it a third time: You are (like) the women of the time of Yūsuf. Command Abū Bakr to lead the people in prayer. So Abū Bakr came out and led the prayer. Then the Prophet ﷺ felt some improvement in his condition, so he came out, dragging himself between two men — it is as if I am seeing his feet, dragging along the ground because of the pain, and marks were being left on the ground. Abū Bakr intended to step back, so the Prophet ﷺ gestured to him to remain in his place. Then he was brought until he sat beside Abū Bakr. It was said to al-A'mash: And the Prophet ﷺ was leading the prayer, and Abū Bakr was praying following his prayer, and the people were praying following Abū Bakr's prayer? He said with a gesture of his head: Yes!

Part of this hadith has been narrated by Abū Dāwūd, from Shu'bah, from al-A'mash. And Abū Mu'āwiyah has added that he sat on the left side of Abū Bakr, and Abū Bakr was standing, leading the prayer.