Muwatta Malik
Book 31, Hadith 36
Arabic hadith text
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ، أَنَّهُ قَالَ قَالَ عُمَرُ بْنُ الْخَطَّابِ الدِّينَارُ بِالدِّينَارِ وَالدِّرْهَمُ بِالدِّرْهَمِ وَالصَّاعُ بِالصَّاعِ وَلاَ يُبَاعُ كَالِئٌ بِنَاجِزٍ .
Translation
Yahya related to me from Malik that he had heard that al-Oasimibn Muhammad said, ''Umar ibn al-Khattab said, 'A dinar for a dinar,and a dirham for adirham, and a sa for a sa. Something to be collectedlater is not to be sold for something at hand. ' "