"The Messenger of Allah ﷺ prayed Zuhr and 'Asr together, and Maghrib and 'Isha' together, when there was no fear and he was not traveling."  

صَلَّى رَسُولُ اللَّهِ ﷺ الظُّهْرَ وَالْعَصْرَ جَمِيعًا وَالْمَغْرِبَ وَالْعِشَاءَ جَمِيعًا مِنْ غَيْرِ خَوْفٍ وَلاَ سَفَرٍ  

"Why?" He said: "So that there would not be any hardship on his Ummah."  

أَنَّ النَّبِيَّ ﷺ كَانَ يُصَلِّي بِالْمَدِينَةِ يَجْمَعُ بَيْنَ الصَّلاَتَيْنِ بَيْنَ الظُّهْرِ وَالْعَصْرِ وَالْمَغْرِبِ وَالْعِشَاءِ مِنْ غَيْرِ خَوْفٍ وَلاَ مَطَرٍ قِيلَ لَهُ لِمَ قَالَ لِئَلاَّ يَكُونَ عَلَى أُمَّتِهِ حَرَجٌ  

"I prayed behind the Messenger of Allah ﷺ eight (Rak'ahs) together and seven (Rak'ahs) together."  

صَلَّيْتُ وَرَاءَ رَسُولِ اللَّهِ ﷺ ثَمَانِيًا جَمِيعًا وَسَبْعًا جَمِيعًا