The Messenger of Allah ﷺ mentioned Ashura and emphasized its importance, then said to those around him, "Whoever among you has not yet eaten, let him fast this day, and whoever has already eaten, let him fast the remainder of his day."
أن رسول الله ﷺ ذكر عاشوراء فعظم منه، ثم قال لمن حوله: من كان لم يطعم منكم فليصم يومه هذا، ومن كان قد طعم منكم فليصم بقية يومه.
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Tabarani reported it in al-Awsat (3255), and Tahawi in his Mushkil (2274), both from the hadith of Abdullah bin Yusuf, who said, "Yahya bin Hamza narrated to us, from Yazid bin Abu Maryam, that Qazaa narrated to him from Abu Saeed," and he mentioned it. Its isnad is sahih.Haythami mentioned it in al-Majma (3/186) and said, "Its narrators are trustworthy." As for Tabarani's statement, "No one narrated this hadith from Qazaa except Yazid," this does not cause harm, for Yazid bin Abu Maryam, Abu Abdullah al-Dimashqi, the imam of the Jami mosque, was deemed trustworthy by Ibn Main and others, and Bukhari cited him as a source. Qazaa is Ibn Yahya al-Basri, a trustworthy narrator among the narrators accepted by the whole community.