Whenever you interact with someone who has wronged you, you should be willing to give them a fresh start in the sense that you will not punish them in your heart for the prior wrongs they have committed against you.
This does not mean you forget what they have done; it means you forgive them for what they have done. They may continue on their way in a destructive manner, but what they do or not do is in their hands, not yours. What is in your hands is to let go of what they have done and not count it against them.
This does not mean you necessarily ignore, tolerate or accept their destructive behavior. It means that you deal with each action on its own without prior prejudice. It means you remain objective and have a pure motive when dealing with the person. And, when it is over, you forgive, wipe the slate clean and be willing to begin again.
This does no good if it’s not real. You can’t force yourself into this. This must come from a willing heart, not an obligation to do right. When you hold on to hurts and mistreatment by others, you are drawn into their world. You engage them on their terms, you become part of what they do and the spirit that drives them. When you forgive and let go the chance to retaliate or smolder resentment and ill feelings, you separate yourself from what has happened and you are free to move back into the light.
This doesn’t mean others are not going to hurt, upset, irritate, and anger you. You wouldn’t be human if you didn’t feel these emotions. But what you do with those feelings at the moment and later, depends on spiritual maturity.
You cannot love if you cannot forgive from the heart. And to forgive means not forgetting but being willing to wipe the slate clean and not hold on to animosity and anger. It means, with each new encounter, giving the person who has wronged you another chance. If the forgiveness is real, from your heart, the person will sense it and it will give him or her another chance to do better--or not. But you have done your part and you walk in the light.
But Rabbi," they said, "a short while ago the Jews tried to stone you, and yet you are going back there?" Jesus answered, "Are there not twelve hours of daylight? A man who walks by day will not stumble, for he sees by this world's light. It is when he walks by night that he stumbles, for he has no light." John 11:9,10
The closer we come to Christ, the more discerning, the more intuitive we become into the motives and expressions of the heart in ourselves and in others.