Sins can be divided as sins in thought, word, deed or omission . Actual sins are the sins we actually commit. Sins do differ in their seriousness and are rightly evaluated according to their gravity. The Church, supported by Scripture and human experience, makes the distinction between mortal and venial sin. Grave matter is specified by the gravity of the offence against the Commandments and by the person offended.
Mortal sin is always a radical possibility because of our human freedom.
Mortal sin kills the life of God's grace in our soul. It turns us away from God, who is our ultimate happiness. Venial sin is a failure to love God or our neighbour as we should, by an act which is not grave or serious. Venial sin does not deprive us of sanctifying grace or our friendship with God, or the promise of eternal happiness with God. However, venial sin does wound our relationship with God and with our neighbour.