Sahih Bukhari Volume 3, Book 34, Hadith 2144

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنْ بَيْعِ حَبَلِ الْحَبَلَةِ، وَكَانَ بَيْعًا يَتَبَايَعُهُ أَهْلُ الْجَاهِلِيَّةِ، كَانَ الرَّجُلُ يَبْتَاعُ الْجَزُورَ إِلَى أَنْ تُنْتَجَ النَّاقَةُ، ثُمَّ تُنْتَجُ الَّتِي فِي بَطْنِهَا‏.‏

Narrated By 'Abdullah bin 'Umar : Allah's Apostle forbade the sale called 'Habal-al-Habala which was a kind of sale practiced in the Pre-Islamic Period of ignorance. One would pay the price of a she-camel which was not born yet would be born by the immediate offspring of an extant she-camel.