Sahih al-Bukhari 1106
Book 18: Shortening the Prayers (At-Taqseer) · Narrated by Salim's father
Arabic
حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنَا سُفْيَانُ، قَالَ سَمِعْتُ الزُّهْرِيَّ، عَنْ سَالِمٍ، عَنْ أَبِيهِ، قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلم يَجْمَعُ بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ إِذَا جَدَّ بِهِ السَّيْرُ.
English translation
Narrated Salim's father:The Prophet (ﷺ) used to offer the Maghrib and `Isha' prayers together whenever he was in a hurry on a journey
Reference: Sahih al-Bukhari 1106, Book of Shortening the Prayers (At-Taqseer). English translation by Dr. Muhammad Muhsin Khan.