Sahih Muslim
The Book of Virtue, Good Manners and Joining of the Ties of Relationship (Kitab Al-Birr was-Salat-I-wal-Adab)
Book Number: 032 / Hadith Number: 6223
Abu Huraira reported it as a marfu' hadith (and the words are): The deeds are presented on every Thursday and Friday and Allah, the Exalted and Glorious. grants pardon to every person who does not associate anything with Allah except the person in whose (heart) there is rancour against his brother. It would be said: Put both of them off until they are reconciled.