I was with Abdullah bin Umar when a goldsmith came to him and said, "Abu Abdul-Rahman, I craft gold, then I sell some of what I have made for more than its weight, taking the extra as compensation for the labor of my hands."Abdullah forbade him from doing that. The goldsmith kept repeating the question, and Abdullah kept forbidding him, until he reached the door of the mosque, or until he reached a mount he intended to ride.Then Abdullah bin Umar said, "A dinar for a dinar, and a dirham for a dirham, with no excess between them. This is what our Prophet entrusted to us, and what we now entrust to you."
كنت مع عبد الله بن عمر، فجاءه صائغ، فقال له: يا أبا عبد الرحمن، إني أصوغ الذهب، ثم أبيع الشيء من ذلك بأكثر من وزنه فاستفضل من ذلك قدر عمل يدي، فنهاه عبد الله عن ذلك، فجعل الصائغ يردد عليه المسألة، وعبد الله ينهاه حتى انتهي إلى باب المسجد أو إلى دابة يريد أن يركبها، ثم قال عبد الله بن عمر: الدينار بالدينار والدرهم بالدرهم لا فضل بينهما، هذا عهد نبينا إلينا، وعهدنا إليكم.
Malik narrated it in the Book of Sales (31) from Humayd bin Qays Makki, from Mujahid, who said what has been mentioned. The goldsmith's name was Wardan Rumi, as mentioned in "Sunan Mathura" by Shafii.As for Ibn Umar's statement, "This is the covenant of our Prophet to us," he meant the companions of the Prophet ﷺ, after it was established for him from the Prophet ﷺ in the hadith of Abu Saeed Khudri and others, as Bayhaqi said in "Marifat Sunan wal Athar" (38/8), because it is established that Ibn Umar used to say something similar to what Ibn Abbas said about currency exchange, until Abu Saeed Khudri told him, "The Prophet ﷺ forbade selling gold for gold except like for like." So he adopted this and retracted his earlier view.On this subject there is also what was narrated from Ata bin Yasar, that Muawiya bought a silver water vessel for less than its worth, or more. He said, Abu Darda said, "The Messenger of Allah ﷺ forbade something like this except like for like."Malik narrated it from Zayd bin Aslam, from Ata bin Yasar, who mentioned it. Nasai (4567), Ahmad (27531), and Bayhaqi (280/5) narrated it through his route. It contains a break in the chain, for Ata bin Yasar did not hear directly from Abu Darda.