Sahih Muslim 1288
Sahih Muslim · Book 15: The Book of Pilgrimage · Departing from 'Arafat to Al-Muzdalifah. It is recommended to pray Maghrib and 'Isha together in Al-Muzdalifah on this night
Sa'id b. Jubair reported:
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ أَبِي، خَالِدٍ عَنْ أَبِي إِسْحَاقَ ، قَالَ قَالَ سَعِيدُ بْنُ جُبَيْرٍ أَفَضْنَا مَعَ ابْنِ عُمَرَ حَتَّى أَتَيْنَا جَمْعًا فَصَلَّى بِنَا الْمَغْرِبَ وَالْعِشَاءَ بِإِقَامَةٍ وَاحِدَةٍ ثُمَّ انْصَرَفَ فَقَالَ هَكَذَا صَلَّى بِنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فِي هَذَا الْمَكَانِ .
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 (ﷺ) led us in prayer at this place.