«كان يجمع بين الظهر والعصر والمغرب والعشاء في السفر»
It was the practice of the Prophet (peace and blessings be upon him):
"While travelling, he (peace and blessings be upon him) would combine the Zuhr and Asr prayers, and the Maghrib and Isha prayers."
Hadith Referenceصحیح الجامع الصغیر / حرف الكاف / 4917