The Institutes, Book 8
Anger Held Back Only for Want of Revenge
But it seems that even this is not where everyone’s vengeance ends. Some can fully satisfy their wrath or their sulking only by carrying out the impulse of anger as far as they are able. We know this to be the case with those who hold back their feelings, not from a desire to calm them, but simply for lack of a chance for revenge. For they can do nothing more to those they are angry with than speak to them without ordinary courtesy. Or it seems as though anger had only to be moderated in action, and not rooted out altogether from its hiding place in our breast. But then, overwhelmed by its shadows, we are unable not only to let in the light of wholesome counsel and of knowledge, but also to be a temple of the Holy Spirit, as long as the spirit of anger lives in us. For wrath that is nursed in the heart, even if it does not injure the people standing by, shuts out the splendor of the radiance of the Holy Spirit just as much as wrath that is shown openly.