Anas reported the Prophet as saying, "Hell will continue to have people thrown into it and ask if there are any more[*] till the Lord of might puts down His foot on it and its parts are collected together. It will then say, `Enough, enough, by Thy might and generosity.' In paradise there will continue to be more room till God creates people for it and causes them to dwell in the extra space in paradise."
*Quran; 1:30
(Bukhari and Muslim.)