Augustine argues that those who sin, deserve to go Hell.
There are two moral problems with this:
Firstly, why would a good, all loving God condemn anyone to eternal suffering? Surely however bad a sin it, is cannot be infinitely evil, and therefore cannot deserve infinite punishment?
Secondly, the logic of Hell does not work. If a sinner is punished, that in no way “undoes” the sin. The victim of the sin is not comforted by the punishment.