John Climacus, The Ladder of Divine Ascent, Step 9, ‘On Malice’ includes:
Remembrance of wrongs comes as the final point of anger. It is a keeper of ins. It hates a just way of life. It is the ruin of virtues, the poison of the soul, a worm in the mind. It is the shame of prayer, a cutting off of supplication, a turning away from love, a nail piercing the soul. It is a pleasureless feeling cherished in the sweetness of bitterness. It is a never-ending sin, an unsleeping wrong, rancor by the hour. A dark and loathsome passion, it comes to be but has no offspring, so that one need not say too much about it. (Trans. Colm Luibheid & Norman Russell)
I was going to comment on the above, but I think the saint of Sinai says it perfectly. Let’s all try to keep from brooding on the wrongs done to us so as to keep our hearts healthy.