Does fasting the Day of ‘Arafah or the tenth of Muharram atone for the grave major sins?
All perfect praise be to Allah, the Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His Slave and Messenger.
It was narrated on the authority of Abu Qataadah, may Allah be pleased with him, that the Prophet said: "I seek from Allah that fasting the Day of ‘Arafah would atone for the sins of the preceding and the coming year, and I seek from Allah that fasting the Day of ‘Aashooraa’ (i.e. tenth of Muharram) would atone for the sins of the preceding year." [Muslim]
When explaining this Hadeeth, An-Nawawi said that this Hadeeth means the sins of the fasting person during these two years. Some scholars said that this Hadeeth means the minor sins. This has been previously clarified when referring to the sins that the ablution atones for. We mentioned there that if there are no minor sins, then hopefully the grave major sins will be alleviated, and if there are no grave major sins, then one’s rank would be elevated.
Thus, the sins that are mentioned in this Hadeeth are the minor sins not the grave major ones as the grave major sins are forgiven through repentance.
Allah Knows best.