(41) باب بَيْعِ التَّمْرِ بِالتَّمْرِ مُتَفَاضِلاً
Umar bin Al-Khattab said:
"The Messenger of Allah said: '(Exchanging) gold for silver is Riba unless it is done on the spot. (Exchanging) dates for dates is Riba unless it is done on the spot. (Exchanging) wheat for wheat is Riba unless it is done on the spot. (Exchanging) barley is Riba unless it is done on the spot."'
Reference: Sunan an-Nasa'i 4558
In-book reference: Book 44, Hadith 110
English translation: Vol. 5, Book 44, Hadith 4562