Here’s a picture of the dam on North Custer just west of Telegraph. When you forgive someone, the effect of the forgiveness is a letting go of the hurtful past, like “water going over a dam.”
To forgive, according to Jesus in Matthew 18, is the “cancel the debt” another person owes you due to a hurt they have caused you. Non-forgiveness “makes the person pay.” Forgiveness is an act of mercy that says, “No longer do you owe me anything.” People who refuse to forgive often are bitter inside. That thing that was done to them is something they hold on to, and in the holding on they withhold things like love and relationship from the other person.
To not forgive someone is to be in a kind of self-imposed prison; to forgive someone is not only to free or release them from the debt they owe you but is also to be free in one’s own heart.
Note: biblically, forgiveness does not mean “forgetting,” even though in my marriage to Linda we have truly forgotten most of the things we have asked each other for forgiveness for.
Also, to forgive a person does not imply that now you are to trust that person.
Finally, from a Christian standpoint, Jesus (in Matthew 18 and the parable of the unforgiving servant) says that because God has forgiven us of so much, how could we even think of not forgiving someone when they hurt us?