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."
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 21084
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."
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 21085
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."
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 21086
Hadith Gradingحکم دارالسلام:صحيح، خ: 4481، وهذا إسناد ضعيف، سويد بن سعيد فيه ضعف، لكنه توبع