But what is the alternative to dutifully 'forgiving' someone if we can't really forgive them? Well, if we are not able to forgive the alternative is not to tell ourselves that we should forgive others. The alternative is an act of will not to seek revenge against that person, and to guard against subtle acts of retaliation. There is a level of authenticity in this kind of non-aggression. We are not trying to make out everything is fine. And it doesn’t extend the harm that has already occurred. And then we can do the spiritual disciplines that I outlined previously. (Here). Maybe, one day, we will forgive the other party.
This question is similar to helping others out of a sense of guilt. The motivation for forgiving others or helping others matters. St Paul says we can do all sorts of incredible feats of self-sacrifice, but without love, nothing is gained. (1Cor 13:1-3) Acting out of guilt
is really about us. Helping others out of guilt is then really about us, not the ones we help. And the 'help' we offer is very easily skewed or distorted when it is offered for our benefit. Moreover, guilt is too closely related to self-disgust to take us very far. And guilt doesn’t build a future but is stuck in the past.
And responding to the needs of others out of guilt will bring unintended consequences. For example, let’s say someone is feeling guilty about the blessings in their life so they decide to be ‘generous’ in money/time/goods toward those they perceive to be less fortunate. And isn’t it handy that the recipient of the largesse then comes to depend on the ‘generosity’ of the giver! I say 'fortunate' because then the feelings of guilt can be easily assuaged. Almost like a vending machine. Whole industries of charity are built on evoking this ‘generosity’.
In the same way, forgiving someone wallowing in guilt won’t relieve their guilt but more likely feed it. The person feeling guilty feels a little better after being forgiven, encouraging them to seek forgiveness over and over. A kind of moral addiction if you like, and Christianity calls such addiction salvation by works. (Or these days we might call it virtue signalling.) And the moral addiction easily becomes a moralistic addiction seeking out other sinners to denounce. We have a plague of this at the moment in western societies.
But to return to the original question: do we have a duty to forgive others? Duty ultimately skews relationships. It is good to remember that. We might think that we should at least mouth forgiveness for the benefit of the person seeking forgiveness. Maybe, but inauthenticity on our part won’t get them very far. Remember, a genuinely remorseful person won’t necessarily require us to forgive them. That's because they won't be seeking forgiveness for their sake but to heal a relationship as best as can be done. So they will let us have our feelings and our work to do rather than require us to forgive them. And genuine remorse means the person has already done some of the work themselves about their actions, who they are, and the future.
Contrast this with the person who needily seeks forgiveness. They will need more than a show on our part. They could come to church and authentically open themselves to the One who has already forgiven them so as to heal and lead them beyond their neediness.