The Prophet ﷺ said, "Boiling water will be poured over their heads. It will penetrate until it reaches their insides, scouring out everything within them until it passes through their feet. This is the melting. Then they will be restored to their original state."
عن النبي ﷺ قال: إن الحميم ليصب على رؤوسهم، فينفذ الحميم حتى يخلص إلى جوفه، فيسلت ما في جوفه حتى يمرق من قدميه، وهو الصهر، ثم يعاد كما كان.
Narrated by Tirmidhi (2582), Ahmad (8864), and Hakim (2/387), all of them through the route of Abdullah bin Mubarak, who said, Saeed bin Yazid informed us, from Abu Samh, from Ibn Hujayra, from Abu Hurairah, and he mentioned it.Tirmidhi said, "This is a hasan sahih hadith and it is rare, and Ibn Hujayra is Abdul-Rahman bin Hujayra al-Masri." End of quote.Hakim said, "This is a hadith sahih in its isnad."I say, its isnad is hasan because of the discussion regarding Abu Samh, who is Darraj bin Saman, and his hadith are hasan except when narrating from Abu Haytham. This particular hadith is from his narration from someone other than Abu Haytham.