It is narrated from Sayyiduna Usamah bin Zayd (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Usury (riba) is only in deferred payment or a (sale with a) period of respite."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 432