Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
tabarani:454ʿAlī b. ʿAbd al-ʿAzīz > Abū Nuʿaym > ʿAbd al-Salām b. Ḥarb > Mughīrah / Ibn Miqsam > ʿAbd al-Raḥman b. Abū Nuʿm

[Machine] Abu Sa'eed Al-Khudri met Ibn Abbas and testified to the Messenger of Allah ﷺ saying, "Gold is to be exchanged for gold and silver for silver, equivalently. So whoever adds more, has indulged in usury." Ibn Abbas then said, "Shall I repent to Allah from what I used to give fatwas about?" Then he returned.  

الطبراني:٤٥٤حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ الْعَزِيزِ ثنا أَبُو نُعَيْمٍ عَنْ عَبْدِ السَّلَامِ بْنِ حَرْبٍ عَنْ مُغِيرَةَ يَعْنِي ابْنَ مِقْسَمٍ عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي نُعْمٍ

أَنَّ أَبَا سَعِيدٍ الْخُدْرِيَّ لَقِيَ ابْنَ عَبَّاسٍ فَشَهِدَ عَلَى رَسُولِ اللهِ ﷺ أَنَّهُ قَالَ «الذَّهَبُ بِالذَّهَبِ وَالْفِضَّةُ بِالْفِضَّةِ مِثْلًا بِمِثْلٍ فَمَنْ زَادَ فَقَدْ أَرْبَى» فَقَالَ ابْنُ عَبَّاسٍ «أَتُوبُ إِلَى اللهِ ﷻ مِمَّا كُنْتُ أُفْتِي بِهِ» ثُمَّ رَجَعَ