Musnad Ahmad 25:1477

Waki’ narrated to us, Malik bin Mighwal narrated to us, from Talhah bin Musarrif, from Sa’id bin Jubayr, from Ibn Abbas, who said: "Thursday, and what is Thursday?" Then I looked at his tears on his cheeks, flowing as if they were strings of pearls. He said: The Messenger of Allah (ﷺ) said: "Bring me the tablet and the inkwell—or the shoulder blade—so that I may write for you a document after which you will never go astray." They said: "The Messenger of Allah (ﷺ) is delirious!"