We were on a military expedition with Malik bin Abdullah al-Khathami in the land of the Romans, when one man went ahead of the people, then dismounted and walked, leading his mount.Malik called out, "Abu Abdullah, why don't you ride?"He replied, "I heard the Messenger of Allah ﷺ say, 'Whoever's feet become dusty in the path of Allah for an hour of the day, they are forbidden to the Fire.' And I am sparing my mount so that I will not have to depend on my people."Abu Musabbih said, "Then the people dismounted, and I never saw a day when more people walked than that day."
غزونا مع مالك بن عبد الله الخثعمي أرض الروم، فسبق رجل الناس، ثم نزل يمشي ويقود دابته، فقال مالك: يا أبا عبد الله ألا تركب؟ فقال: سمعت رسول الله ﷺ يقول: من اغبرت قدماه في سبيل الله ساعة من نهار، فهما حرام على النار وأصلح دابتي لتغنيني عن قومي، قال أبو مصبح: فنزل الناس فلم أر نازلا قط أكثر من يومئذ.
Abdullah bin Mubarak narrated it in Jihad (33) - and this is his wording - and Ahmad (21962) narrated it, via Abdul-Rahman bin Yazid bin Jabir, who said, "Abu Musabbih narrated to me," and he related it. Its isnad is sahih. Not knowing the name of the companion does not affect this.Ibn Hajar said, in the biography of Malik bin Abdullah bin Sinan Khathami in al-Isabah (9/428), "Abu Dawud Tayalisi named him in his Musnad, and Abdullah bin Mubarak named the man mentioned, meaning the companion who narrated the hadith, as Jabir bin Abdullah, and this is the correct view." End of quote.I say, by this he is referring to what Abdullah bin Mubarak narrated in Jihad (32), and from his route Tayalisi (1881), and Ahmad (14947), and Ibn Hibban (4604), all of them via Utba bin Abu Hakeem, from Husayn bin Harmala, from Abu Musabbih, from Jabir bin Abdullah, and he related it. Some of them confined themselves to the raised portion of the hadith, while others mentioned it along with the story.