"I heard 'Umar say: "The Messenger of Allah ﷺ, said: 'Gold for silver is usury, unless it is exchanged on the spot."' (Sahih) Abu Bakr bin Abu-Shaibah said: "I heard sufyan saying: 'Gold for silver." memorize (this).  

قَالَ رَسُولُ اللَّهِ ﷺ الذَّهَبُ بِالْوَرِقِ رِبًا إِلاَّ هَاءَ وَهَاءَ قَالَ أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ سَمِعْتُ سُفْيَانَ يَقُولُ الذَّهَبُ بِالْوَرِقِ احْفَظُوا  

"I came saying. 'Who will exchange Dirham?' Talhah bin 'Ubaidullah, who was with 'Umar bin Khattab, said: 'Show us your gold, then come to us; when our treasure comes, we will give you your silver.' 'Umar said: 'No, by Allah, you will give him silver (now), or give him back his gold, for the Messenger of Allah ﷺ said: "Silver for gold is usury, unless it is exchanged on the spot."'  

عُمَرُ كَلاَّ وَاللَّهِ لَتُعْطِيَنَّهُ وَرِقَهُ أَوْ لَتَرُدَّنَّ إِلَيْهِ ذَهَبَهُ فَإِنَّ رَسُولَ اللَّهِ ﷺ قَالَ الْوَرِقُ بِالذَّهَبِ رِبًا إِلاَّ هَاءَ وَهَاءَ  

'The Messenger of Allah ﷺ said: 'Dinar for Dinar, Dirham for Dirham, with no increase between them. Whoever has need of silver, let him trade gold for it, and whoever has need of gold, let him trade silver for it, and let the transaction be done on the spot."'  

قَالَ رَسُولُ اللَّهِ ﷺ الدِّينَارُ بِالدِّينَارِ وَالدِّرْهَمُ بِالدِّرْهَمِ لاَ فَضْلَ بَيْنَهُمَا فَمَنْ كَانَتْ لَهُ حَاجَةٌ بِوَرِقٍ فَلْيَصْطَرِفْهَا بِذَهَبٍ وَمَنْ كَانَتْ لَهُ حَاجَةٌ بِذَهَبٍ فَلْيَصْطَرِفْهَا بِالْوَرِقِ وَالصَّرْفُ هَاءَ وَهَاءَ