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: 6280
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: It does not seem proper for Siddiq that he should be an invoker of curse. This hadith has been narrated on the authority of Abu Kuraib with the same chain of transmitters.