Ibn Sirin محمد بن سيرين الأنصاري · The Book of Financial Transactions

"The two parties to a transaction have the choicer so long as they have not separated, unless they reach an agreement before parting, and it is not permissible to hasten to leave for fear that the other party may change his mind."

a man told the Messenger of Allah that he was always being cheated. The Messenger of Allah said to him: "When you make a deal, say: There is no intention of cheating" So, whenever the man engages in a deal he says, 'There is no intention of cheating." "(Sahih )

"The Messenger of Allah forbade meeting (the traders on the way) a Muhajhir selling for a Bedouin, keeping the milk in the udder of an animal (so as to increase its price), artificially inflating prices, a man to urge the cancellation of sale already agreed upon and a woman to ask that her sister (in faith) be divorced."

the Messenger of Allah forbade Mukhabarah, Muzabanah and Muhaqalah, and selling dates before they arte fit or eating, and selling them for anything except Dinars and Dirhams. ,"

the Messenger of Allah forbade selling dates in the trees before they ripen or selling ears of corn before the grains become visible and there is no fear of blight. He forbade that to the seller ad the buyer. ,"

a man form among the companions of the Prophet told him, he said: "O Messenger of Allah we cannot buy Saihani dates or 'idhq dates for the same amount of mixed dates (which are of inferior quality). Should we increase (the amount we give in payment for the better quality dates)?" The messenger of Allah said: "Sell them for silver them buy with it"