Sahih Muslim
The Book of Transactions (Kitab Al-Buyu)
Book Number: 010 / Hadith Number: 3858
Abu Huraira (Allah be pleased with him) reported Allah's Messenger (may peace be upon him) as saying: Let dinar be exchanged for dinar, with no addition on either side and dirham be exchanged for dirham with no addition on either side. This hadith has been narrated on the authority of Musa b. Abu Tamim with the same chain of transmitters.