Tafsir of Al-Hajj 22:20

"Therewith shall be melted" (i.e., dissolved) "what is in their bellies" (of the intestines and viscera).

'Abd bin Humayd, al-Tirmidhi—who authenticated it—'Abdullah bin Ahmad in Zawa'id al-Zuhd, and a group [of scholars] recorded from Ibn Abi Hurayrah that when he recited this verse, he said: I heard the Messenger of Allah (ﷺ) say: "Indeed, the boiling water shall be poured onto their heads, penetrating the skull until it reaches their innards, melting whatever is in their innards until it exits through their feet; that is the sahr (melting). Then, they shall be restored as they were."

Al-Hasan and a group recited it as yas-har (with a fathah on the sad and a shaddah on the ha').

The manifest [meaning] is that the Almighty’s saying, "and the skins," is a conjunction linked to "what." Its placement after [the mention of] the bellies—it is said—is either to observe the [rhythmic] pauses, or to signal the extremity of the heat by implying that its effect on the interior is prior to its effect on the exterior, despite their involvement being the opposite. Others said that the effect on the exterior is self-evident, and it was only mentioned to indicate their equality; therefore, the interior was prioritized as it is the more important intended [object].

It is also said that the intended meaning is "and [it] burns the skins," because skins do not melt but rather gather and shrink upon the fire. In al-Bahr, it is mentioned that this is of the type of expression: "I fed her hay and cold water" [i.e., a zeugma]. Some said: There is no need to commit to that, for the states of that realm are a different matter entirely.

It is also said that yas-har means "to distress or scorch," as in the verse: "The sun scorches him, yet he does not melt." In this case, there is no dispute regarding its attribution to the skins. The sentence serves as a circumstantial state (hal) from the "boiling water" or as an initiating sentence.