Maliks Muwatta Book 20, Hadith Number 207.
Section : Doing the Prayer at Muzdalifa.
Yahya related to me from Malik from Yahya ibn Said from Adi ibn Thabit al-Ansari that Abdullah ibn Yazid al-Khatmi told him that Abu Ayyub al-Ansari told him that he prayed maghrib and isha together at Muzdalifa during the farewell hajj, with the Messenger of Allah, may Allah bless him and grant him peace.