Hadith 394
حَدَّثَنَا إِسْحَاقُ بْنُ عِيسَى، أَنْبَأَنَا مَالِكٌ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، رَضِيَ اللَّهُ عَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَهَى عَنْ بَيْعِ حَبَلِ الْحَبَلَةِ.
It was narrated from Ibn `Umar that the Messenger of Allah (ﷺ) forbade selling the offspring of the offspring that is still in the womb of a camel.
Reference : Musnad Ahmad 394
In-book reference : Book 3, Hadith 4