ENOfficial
It was narrated that Sa'eed bin Jubair said: "I was with Ibn 'Umar when he departed from 'Arafah. When he came to Jam' (Al-Muzdalifah), he combined Maghrib and 'Isha', and when he finished he said: 'The Messenger of Allah (ﷺ) did similar to this in this place.'"
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا هُشَيْمٌ، عَنْ إِسْمَاعِيلَ بْنِ أَبِي خَالِدٍ، قَالَ حَدَّثَنَا أَبُو إِسْحَاقَ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، قَالَ كُنْتُ مَعَ ابْنِ عُمَرَ حَيْثُ أَفَاضَ مِنْ عَرَفَاتٍ فَلَمَّا أَتَى جَمْعًا جَمَعَ بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ فَلَمَّا فَرَغَ قَالَ فَعَلَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي هَذَا الْمَكَانِ مِثْلَ هَذَا .
sunnah.com