Musnad Abu Ya'la al-Mawsili 159:128

Abu Musa narrated to us, Abd al-Rahman ibn Mahdi narrated to us, from Zuhayr ibn Muhammad, he said: Musa ibn Abi Tamim narrated to me, from Sa'id ibn Yasar, from Abu Hurayrah, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The dinar for the dinar, and the dirham for the dirham; there is no superiority between them."