The Messenger of Allah (PBUH) forbade two types of business transactions and two ways of dressing. As for the two ways of dressing: Sitting while knees are drawn up in a way that may expose private parts. And praying while wrapping oneself in a single garment leaving no room for arms, unless one crosses one end over his shoulder. As for the two types of forbidden business transactions: The Messenger of Allah (PBUH) forbade touch-selling [obligating someone to buy whatever he touches], throw-selling [trading each other's goods by throwing them at each other], and najsh [fake outbidding without intent to purchase].

Do not go out to meet caravans for trading, do not undercut one another, do not practice najash (fake outbidding), a city dweller should not sell on behalf of a bedouin, and do not leave the udders of camels and sheep unmilked. Whoever buys them after what has been done to them, he has two options after milking them. If he is satisfied with them, he may keep them, and if he is displeased with them, he may returns them along with a sa' of dates [in return for the amount of milk he consumed].

Beware of suspicion, beware of suspicion, beware of suspicion, for suspicion is the falsest of speech. Do not deceitfully outbid one another, do not envy one another, do not compete, do not hate one another, do not turn your backs on one another, and be, O worshippers of Allah, and brothers.