What a difference it would make to one’s life if one were allowed to witness with one’s own eyes the demons of Hell punishing their victims, the roaring of the flames, the mad yelling of the damned, their unbearable moaning and groaning, their writhing for breath and their frantic begging to be allowed to be returned to Earth. Without a doubt, one would become a new person, one would rearrange one’s entire life. If it is the fact that we have not seen Hell that is preventing some people from fearing Allah as they should and being cautious in their daily lives, it should suffice that He has indicated the existence of Hell repeatedly in the Qur’an, describing it in all its details and warning people against it. When the time comes there will be no one who will not see Hell. Only those who fear Allah will be saved from it, the others will be left in it on their knees. (Surah Maryam: 71-72) However, there will be no benefit or advantage to be gained from seeing Hell at this point, because then, one is already beyond the point of no return...
I recommend everybody to read this book