We all have had experiences in our pasts that shape how we view the world today. We live in a world filled with humans, all of them flawed, including ourselves. Certainly there were past relationships with friends and others that took wrong turns, there were times of hurt, betrayal and disappointment. This is common to all of us. It's an imperfect world filled with imperfect people who make mistakes. A problem arises however, when we dwell in the past just as it does when we try to visit the future... it keeps us from enjoying today.
Yet God tells us how to deal with all of it, past and future.
The LORD is merciful and gracious, slow to anger, and plenteous in mercy.
He will not always chide: neither will he keep his anger for ever.
He hath not dealt with us after our sins; nor rewarded us according to our iniquities.
He doesn't reward us according to our iniquities. In human terms, He doesn't try to get even and because of His mercy, He let's go of our past so we can. We are to do the same, that's why we are encouraged to forgive 70 x 7. I think where we get stuck is our need for justice - we demand satisfaction. How can we forgive anyone when we feel they have hurt us on purpose? Well, how does God look at it?
For He knoweth our frame; He remembereth that we are dust
God is more merciful to us than we are to ourselves or others. He remembers how weak we are, that we are only human, that we are "dust" and He does not expect perfection from us. God forgives us the past transgressions and remembers them no more. Can we do that too?
It doesn't seem possible that humans can truly forgive and forget, maybe the forget part is more than we can manage. But the forgiving is absolutely necessary. The funny thing is, the forgiveness we give another isn't really for their benefit, it is for ours.
Holding grudges and the memories of wrongs committed against us close to our hearts, does nothing but poison us. Continuing to nurse that grudge against another does nothing to them, but it binds us and chains us to that person forever. They are free and we are bound. It is only by forgiving and letting go of that wrong that we are freed.
When are bound to the past, we allow those dark clouds of yesterday to block today's sunshine. Today's bright aspect can also be marred by worries about tomorrow that predict yet another storm. It is enough that the sun is shining on us today.