Islamic Ethics of Trading

According to Imam al-Baqir (a.s): “ It is not recommendable to buy what was not seen.” [Reference: Tahtheeb al-Ahkam Ch.1]
The Prophet (s.a.w) prohibited bargaining between daybreak and sunrise.” [Tahtheeb al-Ahkam Ch.7]
On the reprehensibility of deceiving a believer, Imam al-Sadiq (a.s) said: “ deceiving a believer is forbidden.” [Tahtheeb al-Ahkam Ch.7]
The Prophet (s.a.w) said: “ The trader must be mindful of (cautious of) five qualities, otherwise he should not buy or sell: Usury, swearing by God, withholding the defect, commending (the commodity) when he is selling and belittling (it) when he is buying.” [Tahtheeb al-Ahkam Ch.7]
On the undesirability of borrowing from an upstart:
A steward of Imam al-Sadiq (a.s) borrowed food from a man. The man insisted on demanding payment. So, Imam al-Sadiq (a.s) said to the steward: “ Haven’t I forbidden you from asking for a loan someone who had known wealth recently.” [Tahtheeb al-Ahkam Ch.7]
On the reprehensibility of swearing by God during selling, Imam al-Sadiq (a.s) said: “ Beware of swearing, for it erases the blessing and exhausts the commodity.” [Tahtheeb al-Ahkam Ch.7]
On the desirability of keeping up a profession, Imam al-Sadiq (a.s) said: “ If you profit from doing something, keep doing it.” [Tahtheeb al-Ahkam Ch.7]
The Prophet (s.a.w) prohibited that an employee is hired until he knows his wages.” [Reference: Makrim al-Akhlaq]