Narrated `Abdullah bin Zaid: The Prophet said, "The Prophet Abraham made Mecca a sanctuary, and asked for Allah's blessing in it. I made Medina a sanctuary as Abraham made Mecca a sanctuary and I asked for Allah's Blessing in its measures the Mudd and the Sa as Abraham did for Mecca.

Narrated Anas bin Malik: Allah's Apostle said, "O Allah bestow your blessings on their measures, bless their Mudd and Sa." The Prophet meant the people of Medina.

Narrated Salim: that his father said. "I saw those, who used to buy foodstuff without measuring or weighing in the life time of the Prophet being punished if they sold it before carrying it to their own houses."

Narrated Tawus: Ibn `Abbas said, "Allah's Apostle forbade the selling of foodstuff before its measuring and transferring into one's possession." I asked Ibn `Abbas, "How is that?" Ibn `Abbas replied, "It will be just like selling money for money, as the foodstuff has not been handed over to the first purchaser who is the present seller."

Narrated Ibn `Umar: The Prophet said, "He who buys foodstuff should not sell it till he has received it."

Narrated Az-Zuhri from Malik bin Aus: that the latter said, "Who has change?" Talha said, "I (will have change) when our storekeeper comes from the forest." Narrated `Umar bin Al-Khattab: Allah's Apostle said, "The bartering of gold for silver is Riba, (usury), except if it is from hand to hand and equal in amount, and wheat grain for wheat grain is usury except if it is form hand to hand and equal in amount, and dates for dates is usury except if it is from hand to hand and equal in amount, and barley for barley is usury except if it is from hand to hand and equal in amount." (See Riba-Fadl in the glossary).

Narrated Ibn `Abbas: The Prophet forbade the selling of foodstuff before receiving it. I consider that all types of sellings should be done similarly.

Narrated Ibn `Umar: The Prophet said, "The buyer of foodstuff should not sell it before it has been measured for him." Isma`il narrated instead, "He should not sell it before receiving it."

Narrated Ibn `Umar: I saw the people buy foodstuff randomly (i.e. blindly without measuring it) in the lifetime of Allah's Apostle and they were punished (by beating), if they tried to sell it before carrying it to their own houses.