My Christian niece had an affair, divorced her Christian husband without Biblical cause, and married her lover. My sister has forgiven them by faith and as act of her will, but the situation still bothers her. There was no forgiveness sought on their part from anyone; she knows that is not a prerequisite, and she must forgive anyway. However, the question is how does that forgiveness “flesh out” in reality; what does forgiveness DO; how is she to treat them, etc? There are three grand kids involved and this has affected them.
Forgiveness of this sort is a “contrary-to-feelings” choice. In other words we make the decision to forgive even though we don’t feel like doing it. Then we recognize the battle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms (Ephesians 6:12) Your sister still loves her daughter. That makes this a spiritual battle that requires spiritual weapons.
For though we live in the world, we do not wage war as the world does. The weapons we fight with are not the weapons of the world. On the contrary, they have divine power to demolish strongholds. We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ (2 Cor. 10:3-5).
With the aid of prayer and the power of the Holy Spirit we keep taking captive the feelings of anger or disappointment which are against our knowledge of God, making them obedient to Christ until they go away. James 4:7 says when we resist the devil he will flee from us. Your sister will know she’s won when there’s no more strain in her relationship with her daughter.
Choosing to love her daughter doesn’t mean your sister condones her actions. It means she’s chosen to forgive her for them, just as in Christ God forgave us.