In Qawa`id al-Ahkam Allameh Hilli said...
In Qawa`id al-Ahkam Allameh Hilli said: “There are four types of partnership: 1 - Partnership of property (Shirkah al-Amwal) 2 - Partnership by contributing effort and skill (Shirkah al-Abdan) 3 - Partnership based on negotiation (Shirkah al-Mufavezah) 4 - Partnership based on credit and reliability (Shirkah al-Wujuh) However, no forms except the first type are right.”[^3] Therefore, partnership is only correct in regards to property when done subject to the conditions expressed by the jurisprudents.
“Whoever buys or sells should adhere to the following or not engage in trade: 1 - Avoid usury. 2 – Do not swear in trade. 3 – Do not cover up the flaws in his goods. 4 – Do not praise what he wants to sell. 5 – Do not put down what he wants to buy.” [^4] In another tradition in Istikharat we read that Ibn Tavoos quoted on the authority of Muhammad ibn Yahya: “A friend of mine decided to go on a business trip, but postponed it until he could go to visit Imam Sadiq and seek his advice.
When he went to see Imam Sadiq and asked for advice, the Imam said: I advise you to be honest. Do not cover up the flaws of what you want to sell. Do not cheat or fool the one who buys goods from you since it is illegitimate to do so. You should like for others what you like for yourself. Do not swear since false swearing will cause you to go to Hell. A businessman is at a loss unless what he gives and takes is right. Therefore, pray when you decide to start your trip and ask God for good.