عَنِ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا قَالَ قَالَ عُمَرُ رَضِيَ اللَّهُ عَنْهُ عَلِيٌّ أَقْضَانَا وَأُبَيٌّ أَقْرَؤُنَا وَإِنَّا لَنَدَعُ كَثِيرًا مِنْ لَحْنِ أُبَيٍّ وَأُبَيٌّ يَقُولُ سَمِعْتُ مِنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ وَفِي رِوَايَةٍ أَخَذْتُ مِنْ فَمِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فَلَا أَدَعُهُ لِشَيْءٍ وَاللَّهُ تَبَارَكَ وَتَعَالَى يَقُولُ مَا نَنْسَخْ مِنْ آيَةٍ أَوْ نُنْسِهَا نَأْتِ بِخَيْرٍ مِنْهَا أَوْ مِثْلِهَا [سورة البقرة: ١٠٦] ¤ (8451م) (وَعَنْهُ مِنْ طَرِيقٍ ثَانٍ) قَالَ خَطَبَنَا عُمَرُ رَضِيَ اللَّهُ عَنْهُ عَلَى مِنْبَرِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فَقَالَ عَلِيٌّ رَضِيَ اللَّهُ عَنْهُ أَقْضَانَا وَأُبَيٌّ رَضِيَ اللَّهُ عَنْهُ أَقْرَؤُنَا وَإِنَّا لَنَدَعُ مِنْ قَوْلِ أُبَيٍّ شَيْئًا وَإِنَّ أُبَيًّا سَمِعَ مِنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ أَشْيَاءَ وَأُبَيٌّ يَقُولُ لَا أَدَعُ مَا سَمِعْتُ مِنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ وَقَدْ نَزَلَ بَعْدَ أُبَيٍّ كِتَابٌ
Narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) said: Sayyiduna Ali (may Allah be pleased with him) is the most knowledgeable among us in matters of judgment and justice, and Sayyiduna Ubayy (may Allah be pleased with him) is the most knowledgeable among us in recitation, but we leave out several verses from his recitation (because they have been abrogated). He says: I have heard these verses from the Messenger of Allah (peace and blessings be upon him), so I will not leave them for anything, while Allah Almighty has said: {مَا نَنْسَخْ مِنْ آیَۃٍ أَ وْ نُنْسِہَا نَأْتِ بِخَیْرٍ مِنْہَا أَ وْ مِثْلِہَا} … Whatever verse We abrogate or cause to be forgotten, We bring one better than it or similar to it.
(Second chain) Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) says: Sayyiduna Umar (may Allah be pleased with him) addressed us while he was seated on the pulpit of the Prophet, and he said: Sayyiduna Ali (may Allah be pleased with him) is the most knowledgeable among us in matters of judgment and justice, and Sayyiduna Ubayy (may Allah be pleased with him) is the most knowledgeable among us in recitation, but we leave out some of the verses recited by Sayyiduna Ubayy (may Allah be pleased with him). Indeed, Sayyiduna Ubayy (may Allah be pleased with him) heard these verses from the Noble Prophet (peace and blessings be upon him), and he says that whatever he has heard from the Noble Prophet (peace and blessings be upon him), he will not leave it, even though after Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him), some parts of the Noble Qur'an continued to be revealed (due to which some of the previously revealed parts were abrogated).