Musnad Ahmad 25:1138

Yahya ibn Adam narrated to us, from Ibn al-Mubarak, from Yunus, from al-Zuhri, from Abdullah ibn Ka’b, from Ibn Abbas, who said: Ali came out from the presence of the Messenger of Allah (may Allah bless him and grant him peace) during his illness. They said: "How is the Messenger of Allah (may Allah bless him and grant him peace) this morning, O Abu al-Hasan?" He said: "He is, by the praise of Allah, recovered." Al-Abbas said: "Do you not see? I truly see that the Messenger of Allah (may Allah bless him and grant him peace) will pass away from this illness of his. I recognize death in the faces of the sons of Abd al-Muttalib. So come with us to the Messenger of Allah, that we may speak to him. If the matter is to be among us, we will know, and if it is to be in others, we will speak to him so he may advise regarding us." Ali said: "If he says the matter is in others, the people will never give it to us. And by Allah, I will never speak to the Messenger of Allah (may Allah bless him and grant him peace) about this ever."