Bhante Vimalaramsi created a powerful Forgiveness meditation, which he then practiced himself for two years. On his website you will find free resources and excellent instructions.
Last but not least, bhante Ananda has written a booklet, called Open Heart. You can download a free PDF from his website. If you go to the section about Forgiveness Meditation, you will find many more insights on the power of Forgiveness.
Please see the following suttas in relation to forgiveness:
In this sutta, the Buddha doesn’t accept the harm from another. Thus he doesn’t get inflicted to the point that he needs to Forgive.
And this sutta, number 21 the first section, shows the importance of understanding one’s own mistakes and forgiving others’ mistakes.
For more information on how to practice Forgiveness, see