Yahya bin Sa'id al-Ansari يحيى بن سعيد الأنصاري · The Book of Financial Transactions

"We used to trade in the markets of Al-Madinah and we used to call ourselves as-Samasir (brokers) and the people called us that, but the Messenger of Allah came out to s and called us by a name that was better than what we called ourselves. He said: "O merchants (Tujjar)! Selling involves (false) oaths and idle talk, so mix some charity with it,"" (Sahih )

The Messenger of Allah said: "The two parties to a transaction have the choice so long as they have not separated. If they are honest and open, their transaction will be blessed, but if they tell lies and conceal anything the blessing of their transaction will be lost."

the Prophet annulled transaction in the event of crop faioure.

"Any man who pollinates a date-palm tree then sells it, the fruits of the tree are for the one who pollinated it, unless the purchaser stipulated otherwise."

"Pre-emption takes effect in all cases where land has not been divided. But if the boundaries have been sent, and the roads lay out, then there is no pre-emption."

"The Messenger of Allah decreed the principle of pre-emption, and the (rights of) neighbors."