Musannaf Ibn Abi Shaybah 32130 — From whom the Quran is to be taken

Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: Sayyiduna Umar (may Allah be pleased with him) addressed us and said: "Ali (may Allah be pleased with him) is the best judge among us and Ubayy is the best reciter among us, and we have left some things that Ubayy recites. Ubayy used to say: 'I heard the Qur'an from the Messenger of Allah (peace and blessings be upon him), and I will not abandon anything of the word of the Messenger of Allah (peace and blessings be upon him).' Yet the Book was indeed revealed after Ubayy."