Q 2: What is the Tafsir (explanation/exegesis) of
Allah’s saying (meanings of which are translated as):
There is not one of you but will pass over it (Hell): this is with your Lord; a Decree which must be accomplished.
The passing mentioned in the noble Ayah refers to crossing the Sirat (the bridge set over the Fire). Many Hadiths and Athar (narrations from the Companions) prove that this bridge will be set over Hell and people will pass across it; their crossing it will depend upon their deeds.For more benefit, you can refer to [Tafsir
Ibn Kathir]. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.