Definition of Mortal Sin

Mortal sin is characterized as a serious or grievous offense against God. But those terms are often ambiguous according to subject matter and the individual. Willful murder is understood as serious. Can the seriousness nature of willful murder be applied to all situations to the extent that anything less that the act of that offense is not considered mortal? The Ten Commandments can be viewed as mortal if their offenses destroy lives or show a defiance to God. Can this be taken as the guide for mortal sin?

What is mortal sin and venial sin?



Summary from the Compendium issued by Pope Benedict XVI

  1. When does one commit a mortal sin?


One commits a mortal sin when there are simultaneously present: 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.

  1. 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.

Grave matter for mortal sin is yes specified by the Ten commandments …also note too that with many of the commandments other venial matters come under such - for example with lies – while things like lying under oath in court is grave --often other lies are venial in matter. Or there can be theft that is venial.

Some things do not “admit of parvity (smallness) of matter” others do. One cannot “murder a little bit” …but one can lie a little…(though of course let us work to avoid even venial sins).

Thank you for your responses. It is the grave matter in which I have a difficulty in discernment. It may be semantics, but if mortal sin were defined as committing such a horrendous act as to merit damnation in hell, I would have a clearer picture. Admittedly, I’ve struggled with scrupulosity most of my life. I am involved with SA. I have an MA in Catholic religious studies. And it may be that my guide in discerning mortal from venial sin will always be elusive as I look for simplicity. Again, I thank you for hour help. In Jesus through Mary.

Key to such is not only continued formation of conscience --but a *regular confessor *who knows one and can direct one. When one is seeing mortal sin where it is venial or seeing sin where sin is not – or where ones undue fear is guiding one – one very much needs a regular confessor to direct one (at least for some time) – for at least in some matters ones “compass” is not pointing true north.

Remember one needs not only grave matter but also the full knowledge and deliberate consent. If one lacks either or both of those – the sin is venial (if a sin at all).

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