There is only one path to freedom from bitterness of heart and that is forgiveness. Forgiveness is an all or nothing proposition, there is no middle ground here. No “sort of” forgiveness will do.
Forgiveness is an act of the will and motivated by a heart that understands how much you have been forgiven by God and how unworthy you were to be forgiven.
God commands us to forgive one another, even of the deepest hurts. Jesus said our forgiveness is to be without limitations (Matt. 18:22-23). This means that you must forgive completely, holding nothing back. This is quite impossible for you to do alone, and thank God you don’t have to! The Holy Spirit will assist you in applying this command to your heart and life so there is no excuse of “I can’t” because your “can’t” is a won’t!
I routinely hear several reasons as to why people can’t forgive. One of them is “I can’t forgive until I forget.” Nursing the hurt this way will not heal you. The longer you continue to meditate on the hurt (in the name of not forgetting) the deeper bitterness grows.
Another common rational is “time will heal the pain.” This isn’t true. When the hurt is unforgiven bitterness grows because the pain is cherished and nursed along.
I have had women tell me they will forgive when the other person says they are sorry. This can be abused, and this is not the model we have in Christ.
Be on your guard! If your brother sins, rebuke him; and if he repents, forgive him. “And if he sins against you seven times a day, and returns to you seven times, saying, ‘I repent,’ forgive him. Luke 17:3-4