It wasnarrated from Ibn 'Abbas that the Messenger of Allah (ﷺ)said:
"If I live until next year, I will fast the ninth day (ofMuharram)too." (RU)
English reference (RU): Vol. 1, Book 7, Hadith 1736 (RU)
Arabic reference (RU): Book 7, Hadith 1808 (RU)