Abu al-Sha'tha' narrates: I heard Sayyiduna Ibn Abbas (may Allah be pleased with them both) saying: "O Allah, I repent to You of (the verdict on) sarf; it was merely my own opinion, whereas here is Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) narrating it from the Prophet (peace and blessings be upon him)."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 453