From Sahih Muslim (Hadith 3112):
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 (ﷺ) did like this
Reference: Muslim 3112