Chapter on Walking During Travel
Man Lā Yaḥḍuruh al-Faqīh|Volume 2|Book 3|Chapter 36
وَ رُوِيَ: أَنَّ قَوْماً مُشَاةً أَدْرَكَهُمْ رَسُولُ اَللَّهِ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ فَشَكَوْا إِلَيْهِ شِدَّةَ اَلْمَشْيِ فَقَالَ لَهُمُ «اِسْتَعِينُوا بِالنَّسْلِ ».
It is narrated that a group of people who were walking met the Messenger of Allah سبحانه وتعالى (peace and blessings of Allah سبحانه وتعالى be upon him and his family), and they complained to him about the difficulty of walking. Prophet صلى الله عليه وعلى آله وسلم said to them: "Seek assistance through walking briskly (nasl)."
- Ṣaḥīḥ al-Faqīh