Lying- When is it mortal?

[Inquiringperson]

When is lying grave matter?

 

[Pug]

I tend to view this as strongly connected to how it interacts with justice and charity. For example, saying “she wore that yellow ribbon that Sally made for her” could be told to spare the feelings of a young child who gave someone a ribbon, or it could be told during a murder trial, causing the culprit to be misidentified and making a gross miscarriage of justice. In my example you see a very trivial fact go from venial to mortal.

 

[dshix]

When is lying grave matter?

In this case it heavily relies on the circumstances and the intention of the sinner. As the previous poster said, a lie said in a murder trial is liable to be much worse than that in a trivial situation.

This can also be affected by your intention. Let’s say that a lie you tell will actually cause some great catastrophe, but you are unaware and you are lying for a very trivial purpose. This would likely be a venial sin.

 

[Bookcat]

2484 The gravity of a lie is measured against the nature of the truth it deforms, the circumstances, the intentions of the one who lies, and the harm suffered by its victims. If a lie in itself only constitutes a venial sin, it becomes mortal when it does grave injury to the virtues of justice and charity.

scborromeo.org/ccc/p3s2c2a8.htm#III

One good example is Perjury

2476 False witness and perjury. When it is made publicly, a statement contrary to the truth takes on a particular gravity. In court it becomes false witness.276 When it is under oath, it is perjury. Acts such as these contribute to condemnation of the innocent, exoneration of the guilty, or the increased punishment of the accused.277 They gravely compromise the exercise of justice and the fairness of judicial decisions.