Sahih Bukhari Volume 005, Book 058, Hadith Number 183.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 58. Merits of the Helpers in Madina (Ansaar)
Narated By Ibn 'Umar : In the pre-lslamic period of ignorance the people used to bargain with the meat of camels on the principle of Habal-al-Habala which meant the sale of a she-camel that would be born by a she-camel that had not yet been born. The Prophet forbade them such a transaction.