Sahih Bukhari Volume 005, Book 058, Hadith Number 276.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 58. Merits of the Helpers in Madina (Ansaar)
Narated By Abu Al-Minhal 'AbdurRahman bin Mut'im : A partner of mine sold some Dirhams on credit in the market. I said, "Glorified be Allah! Is this legal?" He replied, "Glorified be Allah! By Allah, when I sold them in the market, nobody objected to it." Then I asked Al-Bara' bin 'Azib (about it) he said, "We used to make such a transaction when the Prophet came to Medina. So he said, 'There is no harm in it if it is done from hand to hand, but it is not allowed on credit.' Go to Zaid bin Al- Arqam and ask him about it for he was the greatest trader of all of us." So I asked Zaid bin Al-Arqam., and he said the same (as Al-Bara) did."