It is narrated from Hazrat Ibn Abbas (may Allah be pleased with them both) that Hazrat Umar (may Allah be pleased with him) said: "Ali is the greatest judge among us, and Ubayy is the greatest reciter among us. And we leave many things in Ubayy's recitation." And Ubayy says: "I heard the Prophet Muhammad (peace and blessings be upon him) say this, so I cannot leave it." And Allah Almighty says: "Whatever verse We abrogate or cause to be forgotten, We bring one better than it or similar to it."