I heard Abu Saʿid Al-Khudri saying, "The selling of a Dinar for a Dinar, and a Dirham for a Dirham (is permissible)." I said to him, "Ibn ʿAbbas does not say the same." Abu Saʿid replied, "I asked Ibn ʿAbbas whether he had heard it from the Prophet ﷺ s or seen it in the Holy Book. Ibn ʿAbbas replied, "I do not claim that, and you know Messenger of Allah ﷺ better than I, but Usama informed me that the Prophet had said, 'There is no Riba (in money exchange) except when it is not done from hand to hand (i.e. when there is delay in payment).' "  

أَبُو سَعِيدٍ سَأَلْتُهُ فَقُلْتُ سَمِعْتَهُ مِنَ النَّبِيِّ ﷺ أَوْ وَجَدْتَهُ فِي كِتَابِ اللَّهِ قَالَ كُلُّ ذَلِكَ لاَ أَقُولُ وَأَنْتُمْ أَعْلَمُ بِرَسُولِ اللَّهِ ﷺ مِنِّي وَلَكِنَّنِي أَخْبَرَنِي أُسَامَةُ أَنَّ النَّبِيَّ ﷺ قَالَ لاَ رِبًا إِلاَّ فِي النَّسِيئَةِ