The Prophet ﷺ said, "Hell will continue to have people cast into it while it asks, 'Are there any more?' until the Lord of Glory places His foot upon it. Then it will draw its parts together and say, 'Enough, enough, by Your might and Your generosity!' As for Paradise, there will remain in it a surplus until Allah creates new beings to dwell in that surplus."
عن النبي ﷺ أنه قال: لا تزال جهنم يلقى فيها وتقول: هل من مزيد؟ حتى يضع رب العزة فيها قدمه، فينزوي بعضها إلى بعض، وتقول: قط قط، بعزتك وكرمك، ولا يزال في الجنة فضل حتى ينشئ الله لها خلقا، فيسكنهم فضل الجنة.
Muslim narrated it in "Paradise and the Description of its Bliss" (2848:38), from Muhammad bin Abdullah Razi, who said, Abdul-Wahhab bin Ata narrated to us, regarding His statement , "On the Day We will say to Hell, 'Have you been filled?' and it will say, 'Are there yet more?'" [Qaf 50:30], he informed us, from Saeed (that is, Ibn Abu Aruba), from Qatada, from Anas, and he related it.Bukhari narrated it in "Tawhid" (7384), saying, Khalifa (that is, Ibn Khayyat) said to me, Yazid bin Zuray narrated to us, Saeed narrated to us with it.