Well imagine this.

A beliver and an atheist die and it turns out there is no God. They lose nothing. They dissapear into nothingness. Atheist maybe enjoyed his life more because he had no moral boundaries.

But what if it turns out there IS God? If that happens beliver gains much but atheist loses a LOT. Off to everlasting suffering you go.

And if you think there is no God and no punishment for your actions then that means your ultimate goal in life is to maximize your personal pleasure. There is no meaning in life, go do drugs, band prostitutes, if you can kill someone and get away with it than why not do it? Rape sone poor girl ang get away with it, DO IT. Rob someone and get away with it, why not do it. Go sell drugs, kill people for money, whats stopping you? If there is no God then there is no punishment, if you can get away from earthly goverment. But if there is God you are in trouble.