Sunan al-Nasa'i
The Book of the Times (of Prayer) — Hadith #588
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 .
“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.
Chain of Narration (Isnad)