Dipping into the Catechism 43 391-400

What does the acceptance of God’s mercy require from us? It requires that we admit our faults and repent of our sins. God Himself by His Word and His Spirit lays bare our sins and gives us the truth of conscience and the hope of forgiveness.
What is sin?
It is an offence against God in disobedience to His love. It wounds human nature and injures
human solidarity. Christ in His passion fully revealed the seriousness of sin and overcame it
with His Mercy.
Is there a variety of sins?
There are a great many kinds of sins. They can be distinguished according to their object or
according to the virtues or commandments which they violate. They can directly concern
God, neighbour, or ourselves. They can also be divided into sins of thought, of word, of deed
or of omission (not doing something you should do).
How are sins distinguished according to their gravity?
A distinction is made between mortal (sins that lead to everlasting death) and venial sin.
When does one commit a mortal sin?
One commits a mortal sin when there are present at the same time: grave matter, full
knowledge and deliberate consent. This sin destroys charity in us, deprives us of sanctifying
grace, and, if unrepented, leads us to the eternal death of hell. It can be forgiven in the
ordinary way by means of the sacraments of Baptism and of Penance or Reconciliation.
When does one commit a venial sin?
One commits a venial sin, which is essentially different from a mortal sin, when the matter
involved is less serious or, even if it is grave, when full knowledge or complete consent are
absent. Venial sin does not break the covenant with God but it weakens charity and manifests
a disordered affection for created goods. It impedes the progress of a soul in the exercise of
the virtues and in the practice of moral good. It merits temporal punishment which purifies.
St Augustine of Hippo
How does sin proliferate?
The action of sinning causes a proclivity to sin as well as engendering vice by repetition of
the same acts. One sin can lead to another – for instance lying to cover up the previous sin.
What are vices?
Vices are the opposite of virtues. They are perverse habits which darken the conscience and
incline one to evil. The vices can be linked to the seven, so-called, capital sins which are:
pride, avarice, envy, anger, lust, gluttony and sloth or acedia.
Do we have any responsibility for sins committed by others?
We do have such a responsibility when we culpably cooperate with them.
What are the structures of sin?
Structures of sin are social situations or institutions that are contrary to the divine law. They
are the expression and effect of personal sins