أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا جَدَّ بِهِ السَّيْرُ جَمَعَ بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ ‏.‏

It was narrated from Ibn 'Umar that if the Messenger of Allah (PBUH) was in a hurry to travel, he would combine Maghrib and 'Isha'. Translation Not Available

Book Ref: Sunan An Nisai Book 6 Hadith 605
Web Ref:  Sunan An Nisai Vol 1 Book 6 Hadith 599