The Prophet ﷺ said, "Hell will keep saying, 'Is there any more?' until the Lord of Might places His foot in it, at which point it will say, 'Enough, enough, by Your might!' and its parts will fold together against one another."
قال النبي ﷺ: لا تزال جهنم تقول: هل من مزيد حتى يضع رب العزة فيها قدمه، فتقول: قط قط وعزتك، ويروى بعضها إلى بعض.
Bukhari narrated it in the Book of Oaths and Vows (6661), and Muslim in the Book of Paradise (2848), both from Shayban, from Qatada, who said, Anas bin Malik narrated to us, and he then mentioned the hadith. Bukhari said, Shuba narrated it from Qatada.I say, this is what Bukhari narrated (48480) from Abdullah bin Abu Aswad, who said, Harmi bin Umara narrated to us, who said, Shuba narrated to us, with his chain, and in it it reads, "until He places His foot." Bukhari likewise narrated it in the Book of Tawhid (7384) with the same chain, and Shuba's narration does not specify who places the foot.Then Bukhari said, Khalifa told me, Yazid bin Zuray narrated to us, who said, Saeed narrated to us, from Qatada, from Anas. And from Mutamar, I heard my father, from Qatada, from Anas, from the Prophet ﷺ, who said, "It will keep having people thrown into it, and it will say, 'Is there more?' until the Lord of the worlds places His foot in it, and its parts draw together. Then it will say, 'Enough, enough, by Your might and generosity.' And Paradise will keep having room to spare until Allah brings into being a new creation for it, whom He settles in the surplus of Paradise."This makes clear that the one who places the foot is Allah .As for his saying, "qatt qatt," and in another narration, "qad qad," qatt is pronounced lightly with a sukoon, though pronouncing it with a kasra (qati), without full vowel lengthening, is also permissible, and qad is another dialectal form as well. All of them carry the meaning of "enough" and "sufficient for me."Ibn Khuzayma said, "The narrators of these reports differed over this word in his saying 'qatt' or 'qatt,' some of them transmitting it with the qaf given a fatha, and others with it given a kasra. These are the people of language, the very source from which this matter is drawn, and it is inconceivable that the people of poetry would know the wording of hadith better than the scholars of hadith transmission, who devote themselves to this craft, narrating it, hearing it from the words of scholars, and memorizing it, while most students of Arabic learn the language only from books that are bought or borrowed, without direct oral transmission. We do not deny that the Arabs pronounce some letters of a word with a fatha and others pronounce that same letter with a kasra, owing to the breadth of their language."Muttalibi (meaning Shafii), may Allah have mercy on him, said, "No one can encompass complete knowledge of all the languages of the Arabs except a prophet." End of quote. Kitab Tawhid (1/226-227).