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: 6277
'Imran reported: I perceive as if I am looking towards that dromedary, and in the hadith transmitted on the authority of Thaqafi (the words are):" Unload it and make its back bare for it is accursed."