Why did the Prophet Muhammad (saw) forbid the sale of camels on the basis of Habal-al-Habala?
 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."