Gold is to be paid for by gold, silver by silver, wheat by wheat, barley by barley, dates by dates, salt by salt, like by like, payment being made hand to hand. He who made an addition to it, or asked for an addition, in fact dealt in usury. The receiver and the giver are equally guilty. (Using translation from Muslim 1584e)
قَالَ رَسُولُ اللهِ ﷺ الذَّهَبُ بِالذَّهَبِ وَالْفِضَّةُ بِالْفِضَّةِ وَالتَّمْرُ بِالتَّمْرِ وَالْبُرُّ بِالْبُرِّ وَالشَّعِيرُ بِالشَّعِيرِ وَالْمِلْحُ بِالْمِلْحِ سَوَاءٌ بِسَوَاءٍ مِثْلٌ بِمِثْلٍ مَنْ زَادَ أَوْ اسْتَزَادَ فَقَدْ أَرْبَى الْآخِذُ وَالْمُعْطِي سَوَاءٌ