“This is concerning my question before abu ‘Abd Allah (a.s.), about the case of a man who received Riba’ in ignorance, then he wanted to stay away from Riba’. He (the Imam) said ’What is passed is for him and he must stay away in the coming times.’ He (the Imam) then said, ’Once a man visited abu Ja’far (a.s.), and said, “I have inherited a certain amount of property and noticed that the owner of that property was involved in Riba’. I asked the scholars of law of Iraq and Hijaz and they said that consuming it is not lawful.” Abu Ja’far (a.s.), said, “If you know the Riba’ item distinctly and know the owners of such property, you must return it to them, if you know it is Riba’, take away your capital and leave the rest. If the property is mixed, you can consume them in good health and with pleasure; the property is your property and stay away from what your companion was involved in. The Messenger of Allah, O Allah, grant compensation to Muhammad and his family worthy of their services to Your cause, exempted what had passed of Riba’. One who is ignorant is exempt and is allowed to consume such property. Once he comes to know then it becomes unlawful for him to consume. If he consumes after knowing, it becomes necessary on him what has become necessary on one who consumes Riba’.’””