سُنَنُ النَّسَائِيِّ
Sunan an-Nasa’i 586
The Book of the Times (of Prayer)
The Time When A Traveler May Combine Zuhr And 'Asr Prayers
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا مُفَضَّلٌ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا ارْتَحَلَ قَبْلَ أَنْ تَزِيغَ الشَّمْسُ أَخَّرَ الظُّهْرَ إِلَى وَقْتِ الْعَصْرِ ثُمَّ نَزَلَ فَجَمَعَ بَيْنَهُمَا فَإِنْ زَاغَتِ الشَّمْسُ قَبْلَ أَنْ يَرْتَحِلَ صَلَّى الظُّهْرَ ثُمَّ رَكِبَ .
It was narrated that Anas bin Malik said: "If the Messenger of Allah (ﷺ) was setting out on a journey before the sun passed its zenith, he would delay Zuhr until the time of 'Asr, then he would stop and combine the prayer. If the sun passed its zenith before he set out, he would pray Zuhr and then set off.
Sunan an-Nasa'i, 586Sahih (Darussalam)