From Sahih Muslim (Hadith 3287):
Abu Huraira (Allah be pleased with him) reported:Abu Bakr Siddiq (Allah be pleased with him) sent me during Hajj before the Farewell Pilgrimage for which Allah's Messenger (ﷺ) had appointed him an Amir, among a group of people whom he had ordered to make announcement to the people on the Day of Nahr:" After this year no polytheist may perform the Pilgrimage and no naked person may circumambulate the House." Ibn Shihab stated that Humaid b. Abd al-Rahman said that according to this narration of Abu Huraira (Allah be pleased with him) the day of Hajj al-Akbar (Great Hajj) is this Day of Nahr (10th of Dhu'l-Hijja)
Reference: Muslim 3287