Remembrance or willingness to not remember is a key ethical part of life. There are things which we should always remember and things which we should not remember in at least the sense of acting upon these memories.
We should always remember what God has done for us. It is good to remember what God has spoken through his word and also it is good to remember how God has acted in history.
It is also good to remember the kindness of others. At times it is good to remember our sufferings so we can understand those that suffer.
Certain remembrances are more worrisome. Remembering the transgressions of others against us is in particular worrisome.
We should not remember these things, because as God reminds us he has forgiven our great debt so we should forgive our small debtors.
All our debtors are small in comparison to our debt to God. It may not seem so, but we should see these things by faith.
Of course not remembering transgressions against us implies that we have forgiven, but not forgotten. Forgetting is often dangerous, since unrepentant people often repeat their actions.
There is often a need for both a remembrance and a forgetfulness with certain transgressors. We need to remember that they may not be trust able, but also forget the trespass in a moral sense.