أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ أَنْبَأَنَا سُفْيَانُ، قَالَ سَمِعْتُ الزُّهْرِيَّ، قَالَ أَخْبَرَنِي سَالِمٌ، عَنْ أَبِيهِ، قَالَ رَأَيْتُ النَّبِيَّ صلى الله عليه وسلم إِذَا جَدَّ بِهِ السَّيْرُ جَمَعَ بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ ‏.‏

Sufyan said: "I heard Az-Zuhri say: 'Salim told me that his father said: 'I saw the Prophet (PBUH), if he was in a hurry to travel, joining Maghrib and 'Isha'." Translation Not Available

Book Ref: Sunan An Nisai Book 6 Hadith 607
Web Ref:  Sunan An Nisai Vol 1 Book 6 Hadith 601