Abu al-Minhal said: I asked Sayyiduna al-Bara' bin Azib and Sayyiduna Zayd bin Arqam (may Allah be pleased with them both) about (exchanging) gold. They both said: We were traders in the time of the Messenger of Allah (peace and blessings be upon him), and we asked the Messenger of Allah (peace and blessings be upon him) about (exchanging) gold. He (peace and blessings be upon him) said: "Whatever is hand to hand, in cash, there is no harm in it; but whatever is on credit is not permissible."
(b) Abu al-Minhal said: A partner of mine sold silver on credit until the season, or until the Hajj.
(c) In al-Humaydi's narration: A partner of mine in Kufah sold dirhams for dirhams with an excess between them. In my view this is a mistake, and the correct version is what Ali bin al-Madini and Muhammad bin Hatim narrated; and this is also what is meant in the narration of Ibn Jurayj: the hadith mentions selling one kind for the other — when it is in cash there is no harm, and what is on credit is not permissible — and this is what is meant by the hadith of Sayyiduna Usamah (may Allah be pleased with him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10497