Yahya related to me from Malik that Yahya ibn Said said, "The
Messenger of Allah, mayAllah bless him and grant him peace, ordered
the two Sads to sell a vessel made of either gold or silver from the
booty. They either sold each three units of weight for four units of
weight of coins or each four units of weight for three units of weight
or coins. The Messenger of Allah, may Allah bless him and grant him
peace, said to them, 'You have taken usury, so return it.' "
Muwatta Malik Book 31, Hadith 28