"The Messenger of Allah forbade selling silver for silver and gold for gold, unless it was of equal amounts. And he told us to sell gold for silver however we wanted, and silver for gold however we wanted.
نَهَى رَسُولُ اللَّهِ ﷺ عَنْ بَيْعِ الْفِضَّةِ بِالْفِضَّةِ وَالذَّهَبِ بِالذَّهَبِ إِلاَّ سَوَاءً بِسَوَاءٍ وَأَمَرَنَا أَنْ نَبْتَاعَ الذَّهَبَ بِالْفِضَّةِ كَيْفَ شِئْنَا وَالْفِضَّةَ بِالذَّهَبِ كَيْفَ شِئْنَا