Hadith 4682
Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) was presented with a mule as a gift, and he liked it. We said: O Messenger of Allah (peace and blessings be upon him)! If you permit us to breed mules, more like this could be produced. The Prophet Muhammad (peace and blessings be upon him) said: This will be done by those who do not have knowledge. (Imam Ibn Hibban, may Allah have mercy on him, says:) What is meant by this is: those people who do not have knowledge of the prohibition regarding this.