Ayoub al-Sakhtiyani أيوب السختياني · Wages (Kitab Al-Ijarah)

The Messenger of Allah (ﷺ) as saying: None of you must buy in opposition to one another ; and do not go out to meet the merchandise, (but one must wait) till it is brought down to the market.

The Messenger of Allah (ﷺ) as saying: Do not go out to meet riders to conduct business with them ; none of you must buy in opposition to one another; and do not tie up the udders of camels and sheep, for he who buys them after that has been done has two courses open to him after milking them: he may keep them if he is pleased with them, or he may return them along with a sa' of…

The Messenger of Allah (ﷺ) as saying: Each one of the two parties in a business has an option (to annul it) against the other party so long as they have not separated, except in a conditional bargain.

Hakim asked (the Prophet): Messenger of Allah, a man comes to me and wants me to sell him something which is not in my possession. Should I buy it for him from the market? He replied: Do not sell what you do not possess.