حَدَّثَنَا صَدَقَةُ بْنُ الْفَضْلِ، أَخْبَرَنَا يَحْيَى، عَنْ سُفْيَانَ، عَنْ حَبِيبِ بْنِ أَبِي ثَابِتٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَالَ عُمَرُ أُبَىٌّ أَقْرَؤُنَا وَإِنَّا لَنَدَعُ مِنْ لَحَنِ أُبَىٍّ، وَأُبَىٌّ يَقُولُ أَخَذْتُهُ مِنْ فِي رَسُولِ اللَّهِ صلى الله عليه وسلم فَلاَ أَتْرُكُهُ لِشَىْءٍ قَالَ اللَّهُ تَعَالَى ‏{‏مَا نَنْسَخْ مِنْ آيَةٍ أَوْ نَنْسَأْهَا نَأْتِ بِخَيْرٍ مِنْهَا أَوْ مِثْلِهَا‏}‏

Narrated Ibn `Abbas: `Umar said, Ubai was the best of us in the recitation (of the Qur'an) yet we leave some of what he recites.' Ubai says, 'PI have taken it from the mouth of Allah's Messenger (PBUH) and will not leave for anything whatever." But Allah said "None of Our Revelations do We abrogate or cause to be forgotten but We substitute something better or similar." 2.106 Translation Not Available

Book Ref: Sahih Bukhari Book 66 Hadith 5005
Web Ref:  Sahih Bukhari Vol 6 Book 61 Hadith 527