حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا عَجِلَ بِهِ السَّيْرُ جَمَعَ بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ ‏.‏

Ibn 'Umar reported: When the Messenger of Allah (PBUH) was in a state of hurry on a journey, he combined the sunset and 'Isha' prayers. Translation Not Available

Book Ref: Sahih Muslim Book 6 Hadith 1508
Web Ref:  Sahih Muslim Book 4 Hadith 703 a