Bilal recited the Fajr Azan but the holy prophet did not understand because of intensity of his illness. Aisha said: tell Abu Bakr to offer prayers. Hafsah said: Tell Umar to offer prayers. When the holy prophet heard their expressions, became sad and despite of his bad physical situation, he stood up and placed his arms on shoulders of Imam Ali (a.s) and Fadhl ibn Abbas. He used to haul his feet because of weakness until he arrived in mosque. The holy prophet saw that Abu Bakr has stood at altar and is to offer prayers. His holiness pointed him with his hand to stand behind and he himself went to the altar and offered the prayers and came back home after offering prayers. He swooned and Muslims wept. His holiness opened his eyes and said: give me a paper and ink in order to write you a letter that prevents you to be astray. One of the companions wanted to bring paper and ink but the second said: stay at your place, this man has raved and the holy book is sufficient for us.

 Havadith ul Ayyam, page 67.