Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: Sayyiduna Usamah bin Zaid (may Allah be pleased with them both) informed me that the Messenger of Allah (peace and blessings be upon him) said: "Riba (usury) is only in the case of a loan." Imam Darimi (may Allah have mercy on him) said: That is, (for example) if one pays two dirhams in exchange for one dirham, (then it is riba).
Hadith Takhrijاس روایت کی سند صحیح اور حدیث متفق علیہ ہے۔ دیکھئے: [بخاري 2178، 2179] ، [مسلم 1596] ، [نسائي 4594] ، [ابن ماجه 2257] ، [ابن حبان 5023] ، [الحميدي 555]
Brief Explanation
(The Explanation of Hadith 2615)
Its form is that someone lends one dirham to another and says that after one month, you will have to pay two dirhams; so this is exactly usury (riba).
Sayyiduna Ibn Abbas radi Allahu anhuma used to consider only this as riba (usury): that one type (of commodity) is sold on credit, then only it will be riba. If one dirham is sold for two dirhams in cash with an excess, then it is permissible and correct. Upon this, Sayyiduna Abu Sa'id radi Allahu anhu and others objected, so he admitted his mistake, and there was consensus (ijma') of all the Companions on this: that both delay (credit) and excess (tafadul) in one type (of commodity) are causes of riba and interest.
Some scholars have said: «لا ربا إلا فى النسئية» is abrogated, and some have said: Sayyiduna Ibn Abbas radi Allahu anhuma retracted from this statement.