(13) باب الْجَمْعِ فِي السَّفَرِ بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ
Narrated Ibn `Abbas:
Allah's Messenger (ﷺ) used to offer the Zuhr and `Asr prayers together on journeys, and also used to offer the Maghrib and `Isha' prayers together. Narrated Anas bin Malik: The Prophet (ﷺ) used to offer the Maghrib and the `Isha' prayers together on journeys.
Reference: Sahih al-Bukhari 1107
In-book reference: Book 18, Hadith 27
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 20, Hadith 209