Narrated Shaqiq bin Salama: Once `Abdullah bin Mas`ud delivered a sermon before us and said, "By Allah, I learnt over seventy Suras direct from Allah's Messenger (ﷺ) . By Allah, the companions of the Prophet (ﷺ) came to know that I am one of those who know Allah's Book best of all of them, yet I am not the best of them." Shaqiq added: I sat in his religious gathering and I did not hear anybody opposing him (in his speech).
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عُمَرُ بْنُ حَفْصٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا الأَعْمَشُ، حَدَّثَنَا شَقِيقُ بْنُ سَلَمَةَ، قَالَ خَطَبَنَا عَبْدُ اللَّهِ فَقَالَ وَاللَّهِ لَقَدْ أَخَذْتُ مِنْ فِي رَسُولِ اللَّهِ صلى الله عليه وسلم بِضْعًا وَسَبْعِينَ سُورَةً، وَاللَّهِ لَقَدْ عَلِمَ أَصْحَابُ النَّبِيِّ صلى الله عليه وسلم أَنِّي مِنْ أَعْلَمِهِمْ بِكِتَابِ اللَّهِ وَمَا أَنَا بِخَيْرِهِمْ. قَالَ شَقِيقٌ فَجَلَسْتُ فِي الْحِلَقِ أَسْمَعُ مَا يَقُولُونَ فَمَا سَمِعْتُ رَادًّا يَقُولُ غَيْرَ ذَلِكَ.
sunnah.com