Shia ahadith allow fasting on the day of Ashura?

The followers of Saqifa have pointed out a few ahadith in our authentic books that point towards the permissibility or even virtue of fasting on the day of Ashura. Lets see how Sheikh At-Tusi(rh) reconciled between the ahadith which permitted the fast on this tragic day and the ones that forbade it.

Hadith#1

Sa’ad bin ‘Abdullah from abu Ja’afar from Ja’afar bin Muhammad bin ‘Ubeidullah from ‘Abdullah bin Maymoun al-Qaddah from Imam Ja’afar from his father (as): “The fasting of ‘Ashura removes the sins of a year.”

Hadith#3

Ali bin al-Hassan bin Faddal from Haroun bin Muslim from Masa’adah bin Sadaqah from Imam abu ‘Abdullah from his Father that ‘Ali (as) said: “Fast on ‘Ashura the ninth and tenth for it removes the sins of a whole year.”  

Hadith#6

Ja’far ibn ’Isa his brother who has said the following: “I once asked al-Rida’, ‘Alayhi al-Salam, about fasting on ‘Ashura’ and what people say about it. He (the Imam) said, ‘It is the fast of ibn Marjanah. You are asking me about the day in which the adopted ones of the family of Ziyad for their murdering al-Husayn, ‘Alayhi al-Salam, were fasting. It is an ominous day for the family of Muhammad, ‘Alayhi al-Salam. For people of Islam it is an ominous day. A day, which is ominous for the people of Islam is not a day of fasting or a day of blessing. Monday is an unblessed day because Allah, most Majestic, most Glorious, took His Holy prophet, O Allah, grant compensation to Muhammad and his family worthy of their services to Your cause, from this world. The family of Muhammad, ‘Alayhim al-Salam, has been hurt on Monday, so we took it as an ominous day and our enemies took it as a day of blessing. On the day of ‘Ashura’ al-Husayn, ‘Alayhi al-Salam, was murdered and ibn Marjanah took it for blessing but the family of Muhammad, ‘Alayhim al-Salam, took it as an ominous day. Whoever fasts on this day or takes it for blessing will come in the presence of Allah, most Blessed, most High, with metamorphosed heart and will be raised with those who established the Sunnah of fasting on that day and took it for blessing.’”

Hadith#7

Zurarah asked abu ‘Abd Allah, ‘Alayhi al-Salam, about the fast on the day of ‘Ashura’. He (the Imam) said, ‘Whoever fasts that day, his share for such fast is like the share of ibn Marjanah and the family of Ziyad.’ I then asked, ‘What was their share of that day ? He (the Imam) said, ‘It is the fire.

Sheikh Al Tusi comments:

“The traditions can be reconciled with the point of view that our teacher (Al-Mufid), May God rest his soul, addressed, namely, that the person who, on the day of Ashura’, was affected by the misfortune of the family of Muhammad (s) and who fasted out of sadness over what happened to his relatives, was correct and the person who fasted on that day because of the conviction of our opponents that it was considered to be an excellence of that day and an attainment of blessings and out of the belief in its bestowal and bliss, he sinned and was wrong.” 

📚Al-Istibsar P349-350