12. Sahl ibn Ziyad has narrated from Mu‘awiyah ibn Hakim from al-Hassan ibn Ali ibn Faddal who has said the following: “I once wrote to abu al-Hassan عليه السلام, and asked, ‘I make an advance payment deal with a man for foodstuff and when it is due time I do not have any foodstuff, if I can give him dirhams in exchange. He (the Imam) said, ‘Yes, you can do so.”’