Sahih al-Bukhari, Hadith 2256 ⓘ
Narrated `Abdullah: The people used to sell camels on the basis of Habal-al-Habala. The Prophet forbade such sale. Nafi` explained Habal-al-Habala by saying. "The camel is to be delivered to the buyer after the she-camel gives birth."
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، أَخْبَرَنَا جُوَيْرِيَةُ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ قَالَ كَانُوا يَتَبَايَعُونَ الْجَزُورَ إِلَى حَبَلِ الْحَبَلَةِ، فَنَهَى النَّبِيُّ صلى الله عليه وسلم عَنْهُ. فَسَّرَهُ نَافِعٌ أَنْ تُنْتَجَ النَّاقَةُ مَا فِي بَطْنِهَا.
also referenced under: Book 35, Hadith 16 (In-Book) & Volume 3, Book 35, Hadith 457 (USC-MSA)