Hammad bin Usamah حماد بن أسامة - أبو أسامة · The Chapters on Business Transactions

"The Messenger of Allah (ﷺ) passed by a man who was selling food. He put his hand in it and saw that there was something wrong with it. The Messenger of Allah (ﷺ) said, 'He is not one of us who cheats."'

"O Allah, bless my nation in their early mornings.". It was narrated from Abu Hurairah that the Prophet (ﷺ) said: "Whoever buys a Musarrah, he has the choice (of annulling the deal) for three days. If he returns it, then he must also give a Sa' of dates, not Samra'." Meaning wheat.

'The Messenger of Allah (ﷺ) said: 'Dinar for Dinar, Dirham for Dirham, with no increase between them. Whoever has need of silver, let him trade gold for it, and whoever has need of gold, let him trade silver for it, and let the transaction be done on the spot."'

the Messenger of Allah (ﷺ) forbade selling animals for animals on credit.

"The last thing to be revealed was the Verse on usury but the Messenger of Allah (ﷺ) died before he had explained it to us. So give up usury (interest) and doubtful things."

"The Messenger of Allah (ﷺ) used to accept the invitation of a slave."