Although the chains of transmission of hadiths which denote that fasting on the day of ‘Ashura is prohibited have been disputed by some jurisprudents, we can nonetheless vindicate them and make up for their weak forms and aspects:
1. These hadiths have been recorded in reliable and credible books. Naraqi is quoted to have said, “The weaknesses of chains of transmission for these hadiths cannot prevent us from utilizing them because these hadiths have been recorded in authoritative and credible books, especially those that are situated among authentic hadiths.”26
2. These hadiths are common; perhaps they are even close to a state of successive transmition. Sayyid ‘Ali Tabataba’i writes, “Texts that exhort and encourage fasting on the day of ‘Ashura, because of the weaknesses of their chains of transmission and the absence of someone to put them to general practical application, contradict many hadiths. These are contradictory hadiths that are near to successive transmission; as such it is not at all possible to act upon them even out of laxity…”27
3. Hadiths which prevent fasting on the day of ‘Ashura have credible chains of transmission because Shaykh Tusi has proven that there is opposition and discrepancy between these hadiths and hadiths that encourage and exhort fasting on the day of ‘Ashura. This denotes the credibility of hadiths which prevent fasting on the day of ‘Ashura because contradictions are secondary to the credibility and dependability of the chain of transmission.
4. Hadiths which prevent fasting on the day of ‘Ashura are very credible because they conform with the way of life of the Infallibles (as) and their companions and also the way of life of all those committed and faithful to the religion.
In conclusion, it is preferable to avoid fasting on the day of ‘Ashura.
26. Mustanad al-Shi‘ah, vol. 10, p. 492.
27. Al-Riyad al-Masa’il, vol. 5, p. 467.
Adapted from: "The Uprising of Ashura and Responses to Doubts" by: "‘Ali Asghar Ridwani"