We need to forgive them. Even if we don't want to, we need to. Why? Because Bible commands us to forgive. Ephesians 4:32 says, "And be kind to one another, tenderhearted, forgiving one another, even as God in Christ forgave you." And Colossians 3:13 tells us, "Bearing with one another, and forgiving one another, if anyone has a complaint against another; even as Christ forgave you, so you also must do."
In what we call the Lord's Prayer, Jesus taught, "In this manner, therefore, pray: Our Father in heaven, hallowed be Your name. Your kingdom come. Your will be done on earth as it is in heaven. Give us this day our daily bread. And forgive us our debts, as we forgive our debtors" (Matthew 6:9–12).
And think about this for a moment: we need to forgive for our own sake. Why? Because it tears us up inside. It also turns us into mean, bitter people who are no fun to hang around. All we want to do is talk about what happened to us and how these people hurt us. It is changes us for the worse. We need to forgive.
When you forgive someone, you set a prisoner free: yourself. Forgiven people need to be forgiving people. And if you are not willing to forgive someone else, then I have to wonder whether you understand what God has done for you.
We don't deserve forgiveness. Yet God, in His mercy, forgave all our sins. And there is no greater example of forgiveness than Christ himself hanging on the cross.