(15) باب الصَّرْفِ وَبَيْعِ الذَّهَبِ بِالْوَرِقِ نَقْدًا
Abu Huraira (Allah be pleased with him) reported Allah's Mess-., nger (ﷺ) as saying:
Gold is to be paid for by gold with equal weight, like for like, and silver is to be paid for by silver with equal weight, like for like. He who made an addition to it or demanded an addition dealt in usury.
Reference: Sahih Muslim 1588 c
In-book reference: Book 22, Hadith 107
USC-MSA web (English) reference(deprecated numbering scheme): Book 10, Hadith 3857