The Book of Pilgrimage (Kitab Al-Hajj)
Muslim :: Book 7 : Hadith 3126
'A'isha (Allah be pleased with her) reported Allah's Messenger (may peace be upon him) as saying: There is no day when God sets free more servants from Hell than the Day of 'Arafa. He draws near, then praises them to the angels, saying: What do these want?