It is related from Ka'b ibn Malik, who was one of the three to whom Allah turned that Ibn 'Abbas informed him that 'Ali ibn Abi Talib emerged from the Messenger of Allah, may Allah bless him and grant him peace, in his illness from which he died and the people said, "O Abu'l-Hasan! How is the Messenger of Allah, may Allah bless him and grant him peace, this morning?" He said, "Praise be to Allah, he is well this morning." 'Abbas ibn 'Abdu'l-Muttalib took him by the hand and said to him, "By Allah, in three days time you will be a subject. By Allah, I think that the Messenger of Allah, may Allah bless him and grant him peace, will die of this illness. I recognise death in the faces of the Banu Abdu'l-Muttalib when they are dying. Let us go to the Messenger of Allah, may Allah bless him and grant him peace, and ask him who will have this authority. If it is for us, then we will know that, and if it is for other than us, we will know it and he can advise him to look after us." 'Ali replied, "By Allah, if we ask him for it and he refuses us, then the people would never give it to us afterwards. By Allah, I will not ask it from the Messenger of Allah."

Ka'b bin 'Ujrah (RAA) narrated, ‘I was carried to the Prophet (P.B.U.H.) and the lice were falling over my face. He said, “I did not know that your disease is hurting you as much as what I see. Can you sacrifice a sheep?” I said, ‘No.’ He then said. “Fast for three days or feed six poor people, half a Sa’ each.” Agreed upon.

Allah's Messenger (SAW) said, "A man's prayer offered with another man is purer than his prayer which he offers alone, and his prayer with two men is purer than his prayer with one and if they are more (in number), it is more beloved to Allah, the Mighty the Majestic." [Reported by Abu Dawud and an-Nasa'i. And Ibn Hibban graded it Sahih (authentic)].