The
1994 Catechism of the
Catholic Church describes the double aspect of sin as follows in section 1472:
To
understand this doctrine and practice of the Church, it is necessary to understand that sin has a double
consequence. Grave
sin deprives us of communion with God and therefore makes us incapable of eternal life, the privation of
which is called the
"eternal punishment" of sin. On the other hand every sin, even venial, entails an unhealthy
attachment to creatures,
which must be purified either here on earth, or after death in the state called Purgatory. This
purification frees
one from what is called the "temporal punishment" of sin. These two punishments must not be conceived of
as a kind of vengeance
inflicted by God from without, but as following from the very nature of sin. A conversion
which proceeds from a
fervent charity can attain the complete purification of the sinner in such a way that no
punishment would remain.