It wasnarrated that 'Abdullah bin Mas'ud said:
"The Messenger ofAllah (ﷺ) said, when he was atop his camel with the clipped ears in'Arafat: 'Do you know what day this is, what month this is andwhatland this is?' They said: 'This is a sacred land, a sacredmonth and asacred day.' He said: 'Your wealth and your blood aresacred to you asthis month of yours, in this land of yours, on thisday of yours. Iwill reach the Cistern (Hawd) before you, and I willbe proud of yourgreat numbers before the nations, so do not blackenmy face (i.e.,cause me to be ashamed). I will rescue some people,and some peoplewill be taken away from me. I will say: "O Lord, mycompanions!" andHe will say: "You do not know what innovationsthey introduced afteryou were gone.'"
English reference: Vol. 4, Book 25, Hadith 3057
Arabic reference: Book 25, Hadith 3173