مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1970
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from "Abdullah bin "Umair, the freed slave of Ibn "Abbas, that Ibn ‘Abbas said: The Messenger of Allah (ﷺ) said: "If I live till next year, I will certainly fast the ninth day [of Muharram].”
Musnad Ahmad 1971Qawi (Darussalam)]