The Book of Pilgrimage (Kitab Al-Hajj)
Muslim :: Book 7 : Hadith 2955
Sa'id b. Jubair reported: We came back along with Ibn 'Umar till we reached Muzdalifa. There he led us in the sunset and 'Isha' prayers with one iqama and we then proceeded and he said: This is how Allah's Messenger (may peace be upon him) led us in prayer at this place.