In general, trade is lawful and permissible in Islam, for it is an exchange of products between the buyer and seller. But when harm may be incurred to either of the two parties, the trade is deemed unlawful and prohibited. Allah (swt) says: (O you who believe! Eat not up your property among yourselves unjustly.) [4:29] Islam has deemed the profits made from trade of the purest and best means of earning a living. The Prophet (Peace be upon him) was asked about which earning was best and most pure, and he replied: “Work done by a person using his own hands [i.e. manual labor] and every truthful and sincere trade.” [Ahmad] Islam has enjoined that the individual be truthful while conducting business. The Prophet) said “A Muslim merchant who is truthful and trustworthy will be with the martyrs on the Day of Requital.” [al-Haakim] One should explain any faults which may not be apparent in the product. The Prophet (Peace be upon him) said: “It is impermissible for anyone to sell anything except if he clarifies any fault that may be found in it, and anyone who knows of it should (also) clarify it.” [Ahmad] One should not cheat. Abu Hurairah narrated that the Prophet (Peace be upon him) passed by a pile of food. He put his hands inside it and felt water on his fingers. He said: “What is this, o seller of (this) food?” He said: 'It was left out in the rain, O Messenger of Allah!” He said, “Could you not have put it on top of the food so that people could see it? Whoever deceives (people) is not from us.” [Muslim] A person should be truthful in his dealings and not lie. The Prophet (Peace be upon him) said: “The two parties (involved in the trade) have an option (to cancel the trade) as long as they have not parted. If they have both told the truth and clarified all aspects, their trade will be blessed for them. But if they conceal (faults and other aspects) and lie, the blessings of the trade will be wiped out.” [al-Bukhari and Muslim] One should be easy going while buying and selling, for it is a means to form and strengthen relations between the buyer and seller and does away with the causes of materialism which destroy human and brotherly relationships. The Prophet (Peace be upon him) said: “May Allah have mercy on a person who is easygoing when he buys, sells, or asks the repayment of a loan.” [al-Bukhari] One should not swear oaths when he trades. The Prophet (Peace be upon him) said: “Be careful and stay away from swearing many oaths when trading, for [if he does so falsely] the buyer will buy, but then its blessing will be wiped-out.” [Muslim] It encourages that one take back the sale if a person is regretful of the purchase. The Prophet (Peace be upon him) said: “Whoever takes back the sale of his brother, Allah will take back [the punishment] of his slips on the Day of Resurrection.” [Abu Dagwood & bin Rajah] These are some of the manners and etiquettes which Islam has prescribed. There are many others, but due to brevity, we cannot mention them here. It is sufficient to know that there is no matter in life, except that there is a Qur'anic verse, or Prophetic tradition which addresses it. The reason for this is that a Muslim's entire life would become an act of worship, and a means to increase his good deeds.