Then the Prophet ﷺ said, "I have offered the sacrifice here, but all of Mina is a place of sacrifice." He stood at Arafah and said, "I have stood here, but all of Arafah is a standing place." Then he stood at Muzdalifa and said, "I have stood here, but all of Muzdalifa is a standing place."
حدثنا أحمد بن حنبل حدثنا يحيى بن سعيد حدثنا جعفر حدثنا أبي
ثم قال النبي ﷺ قد نحرت ها هنا ومنى كلها منحر ووقف بعرفة فقال قد وقفت ها هنا وعرفة كلها موقف ووقف بالمزدلفة فقال قد وقفت ها هنا ومزدلفة كلها موقف
Muslim narrated it in the Book of Hajj, chapter on what is reported that Arafah in its entirety is a place of standing, hadith no. 149/1218, from the hadith of Jafar bin Muhammad, transmitted through him. It is also found in Musnad Ahmad, 320/3.