The Book of Virtue, Good Manners and Joining of the Ties of Relationship (Kitab Al-Birr was-Salat-I-wa'l-Adab)
Muslim :: Book 32 : Hadith 6224
Abu Huraim reported Allah's Messenger (may peace be upon him) as saying The deeds of people would be presented every week on two days, viz. Monday and Thursday, and every believing servant would be granted pardon except the one in whose (heart) there is rancour against his brother and it would he said: Leave them and put them off until they are turned to reconciliation.