'Abdullah (b. 'Umar) went and I along with the person belonging to Banu Laith entered (the house) of Sa'id al-Khudri, and he ('Abdullah b. Umar) said: I have been informed that you say that Allah's Messenger (ﷺ) forbade the sale of silver with silver except in case of like for like, and sale of gold for gold except in case of like for like. Abu Sa'id pointed towards this eyes and his ears with his fingers and said: My eyes saw, and my ears listened to Allah's Messenger (ﷺ) saying: Do not sell gold for gold, and do not sell silver for silver except in case of like for like, and do not increase something of it upon something, and do not sell for ready money something, not present, but hand to hand.
Sahih Muslim Book 22, Hadith 94