{O you who have believed, when you travel in the way of Allah}, [until the end of] the verse.
Qatadah's interpretation: This is regarding the affair of Mirdas, a man from Ghatafan. It was mentioned to us that the Prophet of Allah sent an army, led by Ghalib al-Laythi, to the people of Fadak. There were people from Ghatafan among them, and Mirdas was one of them. His companions fled, but Mirdas said to them: "I am a believer, and I will not follow you." The cavalry reached him early in the morning, and when they encountered him, he greeted them with peace, so the companions of the Prophet of Allah called out to him;
﴿يَا أَيهَا الَّذِينَ آمَنُوا إِذَا ضَرَبْتُمْ فِي سَبِيل الله﴾ الْآيَة.
تَفْسِير قَتَادَة: هَذَا فِي شَأْن مرداس رجل من غطفان، ذكر لنا أَن نَبِيَّ الله بعث جَيْشًا عَلَيْهِم غَالب اللَّيْثِيّ إِلَى أهل فدك، وفيهَا نَاس من غطفان، وَكَانَ مرداس مِنْهُم ففر أَصْحَابه، وَقَالَ لَهُم مرداس: إِنِّي مُؤمن وَإِنِّي غير متابعكم؛ فصبحته الْخَيل غدْوَة، فَلَمَّا لقُوَّة سلم عَلَيْهِم، فَدَعَاهُ أَصْحَاب نَبِي الله؛