Verš 31:9

v nichž budou nesmrtelní, a tehdy slib Boží se uskuteční a On mocný je i moudrý.

Tafsir al-Jalalayn

abiding therein (khālidīna fīhā, is a circumstantial qualification [of a future status]), in other words, their abiding therein will have been ordained once they enter it — a promise of God in truth, that is to say, God promised them this and realised it in truth; and He is the Mighty, Whom nothing can overwhelm and so prevent Him from fulfilling His promise and His threat [of chastisement], the Wise, the One Who assigns all things to their rightful places.