The Messenger of Allah ﷺ used to fast on the day of Ashura and would instruct others to fast it as well.
حدثنا عبد الله حدثنا أبو كريب الهمداني حدثنا معاوية بن هشام عن سفيان الثوري عن جابر عن سعد بن عبيدة عن أبي عبد الرحمن
أن رسول الله ﷺ كان يصوم يوم عاشوراء ويأمر به
No references are available.
Its chain of transmission is daif, due to the weakness of Jabir Jafi.Abu Kurayb is Muhammad bin Ala bin Kurayb Hamdani Hafiz, and he is trustworthy. He died in the year 248, at the age of 87.Muawiya bin Hisham Qassar Kufi is trustworthy. Abu Dawud and others confirmed his trustworthiness, and some declared him daif without justification. Bukhari mentioned him in al-Kabir 4/1/337 without recording any criticism of him.This hadith is among the additions of Abdullah bin Ahmad, as it appears in H, while in K and H it is attributed to a narration of Imam Ahmad, which is an error, since Abu Kurayb died later than Ahmad, and Ahmad did not mention him among his teachers. This is further supported by the fact that Haythami mentioned the hadith in Majma al-Zawaid 3:184 and attributed it to Abdullah bin Ahmad and Bazzar.