All of us want happiness. When you look at our world you can see that all sentient beings right down to the smallest insect want only to be happy. Yet when we hold resentment and anger against someone who has wronged us, it is impossible to be happy. Anger and resentment destroy our happiness. 
 
Rabbi Harold Kushner says that if after two days we have not forgiven someone who has wronged us, then it becomes our problem. Letting go of our anger and resentment is important and if we can't do that after two days then we are paying for it by letting it destroy our happiness. Kushner is talking about forgiving the unforgivable - not just everyday kind of annoyances. 
 
I think there are many misconceptions about the practice of forgiving. Some mistakenly believe that by forgiving you are condoning or accepting a grievous act. Or that by forgiving it implies you are weak and will not stand up against those who commit such acts. Another misconception is that if you forgive, justice will be abandoned. But forgiveness is not about helplessly giving up, surrendering, avoiding justice or being weak. Forgiveness is about recognizing the terrible wrong that you hold in your heart, realizing that the wrong can be healed, and working to understand how you came to hold your anger and resentment so dearly so that you do not let it happen again. This process helps you to develop compassion for yourself and others. Forgiveness can be understood as a spiritual practice and was taught by Jesus, Buddha and other great spiritual teachers. 
 
There are many reasons that forgiveness is important. First and foremost, through forgiveness we can begin to liberate our own feelings of anger and resentment. Through the practice of forgiveness we can free our own inner rage. When we forgive an offender, not only does the offender benefit but we also benefit by restoring our peace of mind and happiness. Forgiveness is actually an act of compassion whereby very often we can find real meaning in the worst of life's events. 
 
Alan Wallace illustrates this truth from the Tibetan teachings:  
 
“Imagine walking along a sidewalk with your arms full of groceries, and someone roughly bumps into you so that you fall and your groceries are strewn over the ground. As you rise up from the puddle of broken eggs and tomato juice, you are ready to shout out, "You idiot! What's wrong with you?  
 
Are you blind?" But just before you can catch your breath to speak, you see that  
the person who bumped into you actually  
is blind. He, too, is sprawled in the spilled groceries, and your anger vanishes in an instant, to be replaced by sympathetic concern: "Are you hurt? Can I help you up?" Our situation is like that. When we clearly realize that the source of disharmony and misery in the world is ignorance, we can open the door of wisdom and compassion.  
 
No matter what has happened, we can always return to the greatness of the heart.  
 
We have all heard stories about the mysterious power of compassion and forgiveness in the lives of others. Each time we are inspired by these accounts, we remember that we, too, can forgive.” 
 
Apology and forgiveness are implied throughout the Buddhist texts. Even Jesus when asked how many times one should forgive one's brother said that one should forgive seventy times seven (Matthew 18:22). The Buddha also spoke of forgiveness. But is it possible to forgive the unforgivable? Can we possibly forgive those who commit unspeakable offenses? The book "Chop Wood, Carry Water" relates the well-known poignant Tibetan Buddhist story about two Tibetan monks who encounter each other some years after being released from prison where they had been tortured by their captors. "Have you forgiven them?" asks the first. "I will never forgive them! Never!" replies the second. "Well, I guess they still have you in prison, don't they?" the first says.  
 
Roberto de Vicenzo, the famous Argentine golfer, once won a tournament, and after receiving the check and smiling for the cameras, he went to the clubhouse and prepared to leave. Sometime later he walked alone to his car in the parking lot and was approached by a young woman. She congratulated him on his victory and then told him that her child was seriously ill and near death.  
 
De Vicenzo was touched by her story and took out a pen and endorsed his winning check for payment to the woman. "Make some good days for the baby," he said as he pressed the check into her hand.  
 
The next week he was having lunch in a country club when a PGA official came to his table. "Some of the guys in the parking lot last week told me you met a young woman there after you won the tournament." De Vicenzo nodded. "Well," said the official, "I have news for you. She's a phony. She's not married. She has no sick baby. She fleeced you, my friend."  
 
"You mean there is no baby who is dying? said de Vicenzo.  
 
"Thats right.  
 
"That's the best news I've heard all week," said de Vicenzo.  
 
In the Buddhist tradition there are specific meditation practices that help us cultivate forgiveness. I recommend doing a loving-kindness meditation in three parts. First ask forgiveness of all those you may have harmed through thoughts, words or actions. Second offer forgiveness for any harm others have caused you through their thoughts, words or actions. And finally offer forgiveness to yourself for any harm you have done to yourself. By using the power of meditation, these ideas of compassion become more and more ingrained as a true part of our life and experience.  
 
Another very good practice for developing forgiveness is called tonglen. Tonglen is a meditation practice whereby you exchange self for others in order to alleviate the suffering of others. Tonglen is sometimes referred to as "receiving and taking.” In this practice you actually imagine you are taking in another's suffering as you transform and purify it. Doing this practice for someone who has harmed you is difficult but a very powerful lesson in forgiveness. 
 
How can we expect happiness if we are unwilling to forgive? Mother Theresa said, "If we really want to love, we must learn how to forgive." So, look into your own heart and see what burdens you are still carrying. Transform your anger, and your resentments into acts of compassion. And you may discover that even the most grievous acts can be the catalyst to transform negative emotions into acts of real compassion through forgiveness.