Musnad Ahmad 643:1

Yahya narrated to us, from Isma'il, who said: 'Amir narrated to me, and he said: 'Urwah ibn Mudarris al-Ta'i narrated to me, or informed me, saying: I came to the Messenger of Allah, may Allah bless him and grant him peace, at the station (al-Mawqif). I said: "O Messenger of Allah, I have come from the mountains of Tayy'. I have exhausted my mount and tired myself out. By Allah, I have not left a mountain pass except that I stood upon it. Is there a Hajj for me?" The Messenger of Allah, may Allah bless him and grant him peace, said: "Whoever catches this prayer of ours with us, and has come to Arafat before that, by night or by day, his Hajj is complete, and he has fulfilled his rites."