It is narrated from Sayyiduna Abyad bin Hammal (may Allah be pleased with him) that he came as a delegate to the Messenger of Allah (peace and blessings be upon him) and asked him (peace and blessings be upon him) for the salt mine of Ma'rib as a land grant, and he (peace and blessings be upon him) gave it to him. A man said: "O Messenger of Allah! Do you know what you have given him? You have given him flowing water." He said: So the Messenger of Allah (peace and blessings be upon him) took it back from me. And I asked the Messenger of Allah (peace and blessings be upon him) how much of the arak is protected. He (peace and blessings be upon him) said: "It is protected as far as the feet of the camels do not reach."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 807