Blasphemy

Blasphemy is a direct disparging of the divine goodness. It is therefore a sin in conflict with the faith. For he who has the faith confesses to the divine goodness.

Blasphemy, by its genus or the general essential class of sins to which it belongs, is always a mortal sin.

We have seen that unbelief is the greatest of sins against faith. Blasphemy is an emphatic form of unbelief. Hence, in speaking of sins against faith, blasphemy is often called the worst of sins.

The wicked in hell detest the divine goodness and justice, and thus they blaspheme. It is believable that, after the resurrection of the body at general judgment, human beings in hell will utter their blasphemies audibly.