Yahya related to me from Malik from Musa ibn Abi Tamim from Abu'lHubab Said ibn Yasar from Abu Hurayra that the Messenger of Allah, mayAllah bless him and grant him peace, said, "A dinar for a dinar, adirham for a dirham, no excess between the two."
USC-MSA web (English) reference: Book 31, Hadith 29
Arabic reference: Book 31, Hadith 1320