It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) forbade selling fruit before it ripens (becomes fit to eat), and he (peace and blessings be upon him) said: "When fornication and usury (riba) become widespread in a town, they have indeed made the punishment of Allah lawful upon themselves." This hadith has an authentic chain (sahih al-isnad), but the two Shaykhs (Bukhari and Muslim) did not record it.