Muhammad said: "The firewood of Hell" is what is cast into it. You say: "Hasabtu fulanan hasban" (I pelted someone), with a sukun on the sad; meaning: I threw at him, and what you throw is "hasab" (fuel/thrown object). "You are coming to it, if these had been gods they would not have come to it" (meaning: the devils). "And all of them will remain in it forever," referring to both the worshippers and the worshipped.
قَالَ مُحَمَّد: ﴿حصب جَهَنَّم﴾ مَا أُلْقِي فِيهَا؛ تَقُولُ: حَصَبْتُ فُلَانًا حَصْبًا بِتَسْكِينِ الصَّادِ؛ أَيْ: رَمَيْتُهُ، وَمَا رَمَيْتَ فَهُوَ حَصَبٌ. ﴿أَنْتُمْ لَهَا وَارِدُونَ لَوْ كَانَ هَؤُلَاءِ آلِهَة مَا وردوها﴾ (يَعْنِي: الشَّيَاطِينَ) ﴿وَكُلٌّ فِيهَا خَالِدُونَ﴾ العابدون والمعبودون