Sunan Ibn Majah
2253
Sahih+3

It was narrated that Malik bin Aws bin Hadathan Nasri said:"I heard 'Umar bin Al-Khattab say: 'The Messenger of Allah (ﷺ) said: "Exchanging gold for gold is usury unless it is done on the spot. (Exchanging) wheat for wheat is usury, unless it is done on the spot. (Exchanging) barley for barley is usury unless it is done on the spot. (Exchanging) dates for dates is usury, unless it is done on the spot

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi