Narrated Ibn Ka'b b. Malik:
On the authority of his father: Umm Mubashshir said to the Prophet (ﷺ) during the sickness of which he died: What do you think about your illness, Messenger of Allah (ﷺ)? I do not think about the illness of my son except the poisoned sheep of which he had eaten with you at Khaybar. The Prophet (ﷺ) said: And I do not think about my illness except that. This is the time when it cut off my aorta.
Abu Dawud said: Sometime 'Abd al-Razzaq transmitted this tradition, omitting the link of the Companion, from Ma'mar, from al-Zuhri, from the Prophet (ﷺ), and sometimes he transmitted it from al-Zuhri from 'Abd al-Rahman b. Ka'b b. Malik, 'Abd al-Rahman mentioned that Ma'mar sometimes transmitted the tradition in a mursal form (omitting the link of the Companion), and they recorded it. And all this is correct with us. 'Abd al-Razzaq said: When Ibn al-Mubarak came to Ma'mar, he transmitted the traditions in a musnad form (with a perfect chain) which he transmitted as mauquf traditions (statements of the Companions and not of the Prophet).