In Zad al-Ma’ad, ‘Allamah al-Majlisi says that it is preferable not to observe fasting on the ninth and tenth of Muharram because the Umayyads used to observe fasting on these two days in order to express delight for and to gloat over the martyrdom of Imam al-Husayn (a.s.). Having seen a good omen in the killing of Imam al-Husayn (a.s.), the Umayyads and their fans fabricated many lies against the Holy Prophet (s.a.w.a.) and falsely ascribed to him that he mentioned many merits to be the reward of those who would observe fasting on these two days. On the other hand, the Holy Imams of the Ahl al-Bayt (a.s.) are reported to have warned against observing fasting on these two days in general and on the tenth of Muhammad, the Day of ‘Ashura’, in particular.
The Umayyads – may Allah curse them – used to store up their annual nutriment in their houses on the tenth of Muharram; accordingly, Imam al-Rida(a.s.) is reported to have said, “If one refrains from arranging for any worldly benefit on the tenth of Muharram, Almighty Allah will grant him all his needs for this world and the world to come. If one considers the tenth of Muharram to be the day of his misfortune, sadness, and weeping, Almighty Allah will make the Resurrection Day the day of his delight and happiness; and he will be delighted by us in Paradise. If one considers the tenth of Muharram to be a blessed day and he thus stores up any annual nutriment on that day, Almighty Allah will not bless that which he stored up and will add him to the gang of Yazid, ‘Ubaydullah ibn Ziyad, and ‘Umar ibn Sa’d – may Allah curse them all.”
In conclusion, it is required to suspend any worldly activity on this day and to devote oneself to weeping, mourning the martyrdom of Imam al-Husayn (a.s.), recalling his misfortunes, and ordering one’s family members to hold a consolation ceremony in the same way as one may hold for his dearest people. It is also required to abstain from eating and drinking up to the last hour of the day at which one may break the abstention with a drink of water at least, without intending ritual fasting, since to observe fasting on this day is discommended except in cases of obligatory fasting, such as vow fasting and the like. It is also required not to store up anything in the houses, not to laugh, not to entertain oneself, and not to play. It is recommended, on this day, to invoke Almighty Allah to lay curse on the slayers of Imam al-Husayn (a.s.) one thousand times by saying following statement:
اللّٰهُمَّ الْعَنْ قَتَلَةَ الْحُسَيْنِ عَلَيْهِ السَّلامُ