"The Messenger of Allah forbade us from selling silver for silver unless it was of equal amounts, or selling gold for gold unless it was of equal amounts. The messenger of Allah said: 'Sell gold for silver however you want, and silver for gold however you want."'
نَهَانَا رَسُولُ اللَّهِ ﷺ أَنْ نَبِيعَ الْفِضَّةَ بِالْفِضَّةِ إِلاَّ عَيْنًا بِعَيْنٍ سَوَاءً بِسَوَاءٍ وَلاَ نَبِيعَ الذَّهَبَ بِالذَّهَبِ إِلاَّ عَيْنًا بِعَيْنٍ سَوَاءً بِسَوَاءٍ قَالَ رَسُولُ اللَّهِ ﷺ تَبَايَعُوا الذَّهَبَ بِالْفِضَّةِ كَيْفَ شِئْتُمْ وَالْفِضَّةَ بِالذَّهَبِ كَيْفَ شِئْتُمْ