Ishaq bin Mansur al-Kausaj إسحاق بن منصور بن بهرام - الكوسج · The Book on Business

"I asked Messenger of Allah (ﷺ), I said: 'A man came to me asking to buy something that I did not have. Can I buy it from the market for him and then give it to him?' He said: 'Do not sell what is not with you.'" He said: There are narrations on this topic from 'Abdullah bin 'Umar.

"The Messenger of Allah (ﷺ) gave me on Dinar to purchase a sheep for him. So I purchased two sheeps for him, and I sold one of them for a Dinar. So I returned with the sheep and the Dinar to the Prophet (ﷺ), and I mentioned what had happened and he said: 'May Allah bless you in your business dealings.' After that we went to Kunasah in Al-Kufah, and he made tremendous profits. He was among the wealthiest of…