The Rites of Hajj (Kitab Al-Manasik Wa'l-Hajj)
Dawud :: Book 10 : Hadith 1940
Narrated Abdullah ibn Umar:
The Apostle of Allah (peace_be_upon_him) halted on the day of sacrifice between the jamrahs (pillars at Mina) during hajj which he performed. He asked: Which is this day? They replied: This is the day of sacrifice. He said: This is the day of greater hajj.