Abu Sa'id al-Khudri (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Silver for silver and gold for gold must be equal in amount. Whoever gives more or takes more has engaged in usury; both the giver and the taker are equal (in sin)."
Hadith Referenceالمنتقى ابن الجارود / كتاب البيوع والتجارات / 648
Hadith Gradingغلام مصطفےٰ ظهير امن پوري:صحیح
Hadith Takhrijاز غلام مصطفےٰ ظهير امن پوري:«صحیح مسلم : 1584»