It wasnarrated from Abu Qatadah that the Messenger of Allah (ﷺ)said:
"Fasting the day of 'Ashura', I hope, will expiate for the sinsof the previous year." (TR)
English reference (TR): Vol. 1, Book 7, Hadith 1738 (TR)
Arabic reference (TR): Book 7, Hadith 1810 (TR)