Sayyiduna Ibn Mas'ud (may Allah be pleased with him) says that I have recited seventy surahs after hearing them from the blessed mouth of the Prophet (peace and blessings be upon him), and no one can dispute with me regarding them.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 4372
Hadith Gradingحکم دارالسلام:إسناده حسن من أجل عاصم.