Tafsir of Ar-Rahman 55:44

(They circulate between it): That is, they move back and forth between its fire (and between the Hamim): which is boiling water.

(Reached its intensity): Its cooking and heat have reached their ultimate extremity. Qatadah said: "The Hamim has been boiling since Allah the Almighty created Hell, and the criminal is punished by alternating between being scorched by the Fire and drinking the Hamim."

It is said: They are burned in the Fire, and the Hamim is poured over their heads.

It is also said: When they cry out for help from the Fire, their relief is made to be the Hamim.

It is also said: They are plunged into a valley in Hell where the pus of the people of Hell collects, causing their joints to become dislocated; then they are brought out of it, and Allah the Almighty creates them anew.

From Al-Hasan, he said: "A Hamim that is aan" means molten copper whose heat has reached its limit. It is also said that aan means present [ready/at hand].

Al-Sulami recited: {يُطَافُونَ} (They are made to circulate). Al-A'mash, Talhah, and Ibn Muqsim recited: {يُطَوِّفُونَ} with a damma on the ya, a fatha on the ta, and a kasra on the waw being doubled. It has also been read as {يَتَطَوَّفُونَ} (they circulate), meaning they perform the action of circulating.