It is narrated from Ibn Abbas (may Allah be pleased with them both) that Umar (may Allah be pleased with him), while delivering a sermon from the pulpit, said: "Ali is the greatest judge among us, and Ubayy is the greatest reciter among us. And we leave many things in the recitation of Ubayy, and Ubayy says: 'I heard the Prophet (peace and blessings of Allah be upon him) say this, so I cannot leave it,' even though the Qur'an continued to be revealed after that."