My partner sold silver to be paid in the (Hajj) season or (in the days of) Hajj. He (my partner) came to me and informed me, and I said to him: Such transaction is not desirable. He said: I sold it in the market (on loan) but nobody objected to this. I went to al-Bara' b. 'Azib and asked him, and he said: Allah's Apostle ﷺ came to Medina and we made such transaction, whereupon he said: In case the payment is made on the spot, there is no harm in it, and in case (it is 'sold) on loan, it is usury. You better go to Zaid b. Arqam, for he is a greater trader than I; so I went to him and asked him, and he said like it.  

بَاعَ شَرِيكٌ لِي وَرِقًا بِنَسِيئَةٍ إِلَى الْمَوْسِمِ أَوْ إِلَى الْحَجِّ فَجَاءَ إِلَىَّ فَأَخْبَرَنِي فَقُلْتُ هَذَا أَمْرٌ لاَ يَصْلُحُ قَالَ قَدْ بِعْتُهُ فِي السُّوقِ فَلَمْ يُنْكِرْ ذَلِكَ عَلَىَّ أَحَدٌ فَأَتَيْتُ الْبَرَاءَ بْنَ عَازِبٍ فَسَأَلْتُهُ فَقَالَ قَدِمَ النَّبِيُّ ﷺ الْمَدِينَةَ وَنَحْنُ نَبِيعُ هَذَا الْبَيْعَ فَقَالَ مَا كَانَ يَدًا بِيَدٍ فَلاَ بَأْسَ بِهِ وَمَا كَانَ نَسِيئَةً فَهُوَ رِبًا وَائْتِ زَيْدَ بْنَ أَرْقَمَ فَإِنَّهُ أَعْظَمُ تِجَارَةً مِنِّي فَأَتَيْتُهُ فَسَأَلْتُهُ فَقَالَ مِثْلَ ذَلِكَ  

I asked al-Bara' b. Azib about the exchange of (gold for silver or vice versa), whereupon he said: you better ask Zaid b. Arqam for he knows more than I. So I asked Zaid but he said: You better ask al-Bara' for he knows more than I. Then both of them said: Messenger of Allah ﷺ forbade the sale of silver for gold when payment is to be made in future.  

سَلِ الْبَرَاءَ فَإِنَّهُ أَعْلَمُ ثُمَّ قَالاَ نَهَى رَسُولُ اللَّهِ ﷺ عَنْ بَيْعِ الْوَرِقِ بِالذَّهَبِ دَيْنًا  

It is to be made on the spot. This is what I heard (from Messenger of Allah (may peace be upon him ).  

نَهَى رَسُولُ اللَّهِ ﷺ عَنِ الْفِضَّةِ بِالْفِضَّةِ وَالذَّهَبِ بِالذَّهَبِ إِلاَّ سَوَاءً بِسَوَاءٍ وَأَمَرَنَا أَنْ نَشْتَرِيَ الْفِضَّةَ بِالذَّهَبِ كَيْفَ شِئْنَا وَنَشْتَرِيَ الذَّهَبَ بِالْفِضَّةِ كَيْفَ شِئْنَا قَالَ فَسَأَلَهُ رَجُلٌ فَقَالَ يَدًا بِيَدٍ فَقَالَ هَكَذَا سَمِعْتُ  

Messenger of Allah ﷺ prohibited us. The rest of the hadith is the same.  

نَهَانَا رَسُولُ اللَّهِ ﷺ بِمِثْلِهِ