Yahya related to me from Malik that Yahya ibn Said said, "The Messenger of Allah, may Allah 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'. "
The Prophet Muhammad also taught that we should always strive to do what is right even if it means sacrificing something for ourselves or going out of our way to help someone else in need. He showed this through his own example when he ordered the two people to return what they had taken as usury even though it was not their fault but rather due to a mistake made by them while exchanging goods for money. This teaches Muslims that we must always strive towards doing good deeds no matter how small they may seem because Allah rewards those who are sincere in their intentions and actions towards helping others without expecting anything in return from them except His pleasure and reward from Him alone.