سنن النسائي

It was narrated that abu Al-Minhal said: "Sharik sold some silver on credit for me. He came to me and told me. And I said: 'This is not correct.' He said; 'By Allah, I did this transaction in the market and no one criticized me .' So I went to Al-Bara bin Azib and asked him about that. He said: 'The Prophet (ﷺ) came to us in Al-Madinah and we used to do this kind of transaction, but he said: Whatever is hand to hand, there is nothing wrong with it, but whatever is on credit, is Riba. Then he said to me: 'Go to Zaid bin Arqam.' So I went to him and asked him, and he said the same thing."