Sahih Muslim , Book 4, Hadith 1519 (USC-MSA) ⓘ
Mu'adh b. Jabal reported: The Messenger of Allah combined in the expedition to Tabuk the noon prayer with the afternoon prayer and the sunset prayer with the 'Isha' prayer. He (one of the narrators) said: What prompted him to do that? He (Mu'adh) replied that he (the Holy Prophet) wanted that his Ummah should not be put to (unnecessary) hardship.
حَدَّثَنَا يَحْيَى بْنُ حَبِيبٍ، حَدَّثَنَا خَالِدٌ، - يَعْنِي ابْنَ الْحَارِثِ - حَدَّثَنَا قُرَّةُ بْنُ خَالِدٍ، حَدَّثَنَا أَبُو الزُّبَيْرِ، حَدَّثَنَا عَامِرُ بْنُ وَاثِلَةَ أَبُو الطُّفَيْلِ، حَدَّثَنَا مُعَاذُ بْنُ جَبَلٍ، قَالَ جَمَعَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي غَزْوَةِ تَبُوكَ بَيْنَ الظُّهْرِ وَالْعَصْرِ وَبَيْنَ الْمَغْرِبِ وَالْعِشَاءِ . قَالَ فَقُلْتُ مَا حَمَلَهُ عَلَى ذَلِكَ قَالَ فَقَالَ أَرَادَ أَنْ لاَ يُحْرِجَ أُمَّتَهُ .
also referenced under: Book 6, Hadith 63 (In-Book) & Hadith 706 (Reference)