Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that when the Messenger of Allah (peace and blessings be upon him) fasted on the day of Ashura, he ordered that it be fasted. They said: O Messenger of Allah (peace and blessings be upon him)! This is a day that the Jews and the Christians venerate. The Messenger of Allah (peace and blessings be upon him) said: "When the next year comes, we will, if Allah wills, also fast on the 9th." The narrator says: The next year had not yet come when he (peace and blessings be upon him) passed away.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8401