Hawzah News Agency – Imam Sadiq peace be upon him says:

مَن أرادَ التّجارةَ فلْيَتَفقَّهْ في دِينِهِ لِيَعلمَ بذلكَ ما يَحِلُّ لَهُ مِمّا يَحْرُمُ علَيهِ، ومَن لَم يَتَفقّهْ في دِينِهِ ثُمّ اتّجَرَ تَورَّطَ الشُّبُهاتِ.

'Whoever wants to trade must learn his religion thoroughly in order to know what is allowed and what is forbidden for him; and whoever does not learn about his religion and then practices trading will certainly get entangled into uncertainties and problems.'

Source: Wasa'il al-Shia, v. 12, p. 283, no. 4