According to the Qur'ān, the incident of mi`rāj
(ascension) of the Prophet (sws) was not a physical journey. It was more of a
spiritual journey and took place in a vision shown to him. The Qur’ān says:
And the vision which We showed you [O Prophet!], We made
it a trial for men. (17:60)
Dreams and visions, it should be borne in mind have
remained a mode of revelation for the Prophets of Allah. Through them, they
are imparted information by the Almighty in a symbolic form for the guidance
of the Ummah.
In this particular vision, the Prophet (sws) was shown
the various sections of Hell and the various forms of punishments being
administered to its dwellers. These sights of Hell are enshrouded in the veil
of symbolism and must not be taken literally. As such, the vision only
symbolizes a future event.
Of course! people will enter Heaven or Hell on the Day
of Judgement after their deeds have been judged.