Can an angry thought be a mortal sin?

[per_passionem_eius]

Of course there are degrees in sin. I'm only repeating what priests have told me: it's a mortal sin to consent to a thought that wishes serious harm to another, or even to myself, or rejoices in the serious harm done to someone, or even myself.

I've been told, and have verified it with experience, that our thoughts are often involuntary, and they can remain involuntary for a period of time, during which, even if they are of this type, i.e. wishing someone's death, they aren't mortally sinful because there was no consent. They were akin to dreams, for which we are also not responsible. These kind can be habit-forming.

But when we catch ourselves, and wake up, so to speak, and refuse to indulge in them anymore, and refuse to consent to them, there is no sin, not even venial. Even if the thoughts never stop, as long as we refuse to consent to them, there's no sin. But if we consent to them, i.e. indulge in them, or enjoy them, they're mortally sinful.

This is what I've learned from more than one priest in spiritual direction.

[Warrenton]

It depends on what one means by "thought."  Frequent anger, and frequent thoughts that result from anger, fantasies based on anger, all threaten the health of our souls, because they habituate us to giving in to our passions.  The Philokalia speaks a lot about this, as did the desert Fathers and Mothers.