Fitr bin Khalifah says: I said to Ata: O Abu Muhammad, Ikrimah used to say that Sayyiduna Ibn Abbas (may Allah be pleased with them both) used to say: The Book (the Qur'an) has taken precedence over wiping over the leather socks. He (Ata) said: Ikrimah (may Allah have mercy on him) was mistaken. Sayyiduna Ibn Abbas (may Allah be pleased with them both) used to say: Wipe over the leather socks, even if you have come out of the toilet. It is possible that Sayyiduna Ibn Abbas (may Allah be pleased with them both) said what Ikrimah (may Allah have mercy on him) narrated from him, and then, when confirmation reached him from the Prophet (peace and blessings be upon him) that he (peace and blessings be upon him) wiped after the revelation of Surah al-Ma'idah, he said what Ata (may Allah have mercy on him) reported.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1293