Musnad Ahmad 3:126

'Abdullah narrated to us, Ahmad ibn 'Abdah al-Basri narrated to us, al-Mughirah ibn 'Abd al-Rahman ibn al-Harith al-Makhzumi narrated to us, my father 'Abd al-Rahman ibn al-Harith narrated to me, from Zayd ibn 'Ali ibn Husayn, from his father 'Ali ibn Husayn, from 'Ubayd Allah ibn Abi Rafi', the freed slave of the Messenger of Allah (may Allah bless him and grant him peace), from 'Ali ibn Abi Talib: That the Messenger of Allah (may Allah bless him and grant him peace) stood at 'Arafah while Usamah ibn Zayd was riding behind him. He said: "This is the station, and all of 'Arafah is a station." Then he departed at a gentle pace, and the people began to strike to the right and to the left, while he turned and said: "Tranquility, O people! Tranquility, O people!" Until he came to al-Muzdalifah, and he combined the two prayers. Then he stood at al-Muzdalifah, and he stood at Qazah, and he had al-Fadl ibn al-'Abbas ride behind him, and he said: "This is the station, and all of al-Muzdalifah is a station." Then he departed and began to travel at a gentle pace, while the people were striking to the right and to the left, and he was turning and saying: "Tranquility, O people! Tranquility." And he mentioned the rest of the hadith in full.