"Ibn 'Umar and I went to Abu Sa'eed and he narrated to us: 'the Messenger of Allah ﷺ said - and I heard him with these [two] ears: "Do not sell gold for gold except kind for kind, nor sliver for silver except kind for kind, do not exchange more of one than the other, and do not sell what is not present from them for what is present."  

انْطَلَقْتُ أَنَا وَابْنُ عُمَرَ إِلَى أَبِي سَعِيدٍ فَحَدَّثَنَا أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ سَمِعَتْهُ أُذُنَاىَ هَاتَانِ يَقُولُ لاَ تَبِيعُوا الذَّهَبَ بِالذَّهَبِ إِلاَّ مِثْلاً بِمِثْلٍ وَالْفِضَّةَ بِالْفِضَّةِ إِلاَّ مِثْلاً بِمِثْلٍ لاَ يُشَفُّ بَعْضُهُ عَلَى بَعْضٍ وَلاَ تَبِيعُوا مِنْهُ غَائِبًا بِنَاجِزٍ  

"I would sell camels at Al-Baqi', so I would sell them for Dinar but take in place of them Dirham, and, I would sell for silver and take Dinar in its place. So I went to the Messenger of Allah ﷺ and found him leaving the house of Hafsah. I asked him about that and he said: 'There is no harm in that when it (equals) the price.'"  

كُنْتُ أَبِيعُ الإِبِلَ بِالْبَقِيعِ فَأَبِيعُ بِالدَّنَانِيرِ فَآخُذُ مَكَانَهَا الْوَرِقَ وَأَبِيعُ بِالْوَرِقِ فَآخُذُ مَكَانَهَا الدَّنَانِيرَ فَأَتَيْتُ رَسُولَ اللَّهِ ﷺ فَوَجَدْتُهُ خَارِجًا مِنْ بَيْتِ حَفْصَةَ فَسَأَلْتُهُ عَنْ ذَلِكَ فَقَالَ لاَ بَأْسَ بِهِ بِالْقِيمَةِ  

From Malik bin Aws bin Hadathan that he said: "I once said: 'Who can change some Dirham?' So Talhah bin 'Ubaidullah - and he was with 'Umar bin Al-Khattab - said: "Leave your gold with us, then return to us when our servant comes and we will give you your silver." 'Umar bin Al-Khattab said: "No! By Allah! Either give him his silver or return his gold to him. Indeed the Messenger of Allah ﷺ said: 'Silver for gold is Riba, except for hand to hand; and wheat for wheat is Riba except for hand to hand; and barley for barley is Riba except hand to hand; and dried-dates for dried-dates is Riba except for hand to hand.'"  

عُمَرُ كَلاَّ وَاللَّهِ لَتُعْطِيَنَّهُ وَرِقَهُ أَوْ لَتَرُدَّنَّ إِلَيْهِ ذَهَبَهُ فَإِنَّ رَسُولَ اللَّهِ ﷺ قَالَ الْوَرِقُ بِالذَّهَبِ رِبًا إِلاَّ هَاءَ وَهَاءَ وَالْبُرُّ بِالْبُرِّ رِبًا إِلاَّ هَاءَ وَهَاءَ وَالشَّعِيرُ بِالشَّعِيرِ رِبًا إِلاَّ هَاءَ وَهَاءَ وَالتَّمْرُ بِالتَّمْرِ رِبًا إِلاَّ هَاءَ وَهَاءَ