وَعَنِ ابْنِ عُمَرَ قَالَ: نَهَى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَن بَيْعِ حَبَلِ الْحَبَلَةِ وَكَانَ بَيْعًا يَتَبَايَعُهُ أَهْلُ الْجَاهِلِيَّةِ كَانَ الرَّجُلُ يَبْتَاعُ الْجَزُورَ إِلَى أَنْ تُنتَجَ النَّاقةُ ثمَّ تُنتَجُ الَّتِي فِي بطنِها

Ibn ‘Umar said that God's Messenger forbade the transaction called habal al-habala which was one entered into in pre-Islamic times, whereby a man bought a she-camel which was to be the offspring of a she-camel which was still in its mother’s womb. (Bukhari and Muslim.)