On first thought, the idea that we need to always forgive regardless of whether the other person repents seems right but does it stand up to a close examination of Scripture? After all, Scripture is the final authority in matters of faith and Scripture does say a lot about forgiveness.
I was first faced with this question in a course I took at seminary on Counseling Victims of Childhood Sexual Abuse. It was the contention of the professor that telling the victim of abuse that they need to forgive an unrepentant victimizer is wrong. What the professor said did not make sense to me at the time so I went away and looked up all the passages in the Bible on repentance.
I wanted to make a pile of passages which teach bilateral forgiveness and another pile which teach unilateral forgiveness. In the end, every passage which seemed to teach unilateral forgiveness when examined in context, failed to teach it. I was left with the conclusion that the Bible teaches bilateral forgiveness.
I have come to view forgiveness as an exchange where one party repents and the other forgives.
Here is a paper I wrote for that class on Healing for the Victim of Childhood Sexual Abuse. The paper has a section titled "Role of Forgiveness" starting on page 11.
The popular view is that we are always called to forgive, but God does not seem to operate this way Himself. Forgiveness is always offered by God, but not always received by people. We need to repent of our sins in order to receive God's forgiveness.
Would God ask us to forgive without repentance if God does not do the same? Intuitively this seems problematic. God would be asking us to do something differently than He does Himself. Certainly God treats those who are unrepentant with love but does He forgive them? If so, wouldn't this necessitate a form of universalism where everyone automatically gets forgiven regardless of repentance?
If forgiveness is bilateral, ie, based on repentance, then how do we understand the passages which seem to imply always forgiving? Passages such as Matt 18:35 which say:
My heavenly Father will also do the same to you, if each of you does not forgive his brother from your heart."This passage needs to be read within the context of the rest of the chapter, particularly verses 15-17. In these verses, repentance is the key to forgiveness. The person what was wronged is required to forgive the one who repents. If the person does not repent, in the end the person is to be shunned.
David Augsburger has a book, The New Freedom of Forgiveness, where he presents this idea in a developed form.
