Sahih Muslim
The Book of Pilgrimage (Kitab Al-Hajj)
Book Number: 007 / Hadith Number: 2953
Sa'id b. Jubair reported that he observed the sunset and 'Isha' prayers at Muzdalifa with (one) iqama. He narrated on the authority of Ibn 'Umar (Allah be pleased with them) that he observed prayers like this. and Ibn 'Umar (Allah be pleased with them) narrated that Allah's Apostle (may peace be upon him) did like this. Shu'ba reported this hadith with the same chain of transmitters and said: He (the Holy Prophet) observed the two prayers (together) with one iqama.