On November 3, 2022 Prof. B. Gritters (professor of Practical Theology and NT Studies in the PRC Seminary) gave a public lecture on "The Confusion about Forgiveness" in Grace PRC in Standale, MI.
The audio recording of that speech is now available (use the link provided here), but you may also have a glimpse into what Prof. Gritters means by his title from a recent editorial he wrote for the Reformed magazine, the Standard Bearer.
In the November 1, 2022 issue, Prof. Gritters wrote on "The sin of forgiveness." Here's the beginning of that editorial, which will also help you understand the perspective Prof. Gritters makes in his lecture.
"It may be hard to believe that, in certain circumstances, it may be sinful to say, “I forgive you.” But it should not be surprising. One of the most blessed activities among the people of God—the declaration from one sinner to another, “I forgive you”—can be misused to serve a purpose the very opposite of the one for which the Lord designed it.
"Christians should not only recognize that this is possible, they should expect it. Since the devil masquerades as an angel of light and recruits men and women to work on his behalf (II Cor. 11:14,15), we should not be ignorant of his devices (II Cor. 11:2), not in this case either. The devil is so determined to ruin the blessed works of God that he can, in fact, take what is supposed to be at the pinnacle of Christian conduct and make it antichristian.
"It is possible that the act of forgiveness becomes an act of sin.
"The primary way in which this sin is committed is when the response to a very serious sin is automatically to declare, “I forgive you.” Those who have done so may not realize that such was sinful, but we must be instructed to see it as sinful.
"I first saw the expression, “The Sin of Forgiveness,” in the title of a newspaper article some 25 years ago in which the author expressed horror at such a declaration. A fourteen-year-old high school student in West Paducah, KY, murdered three of his teenaged classmates while they were praying. Almost immediately, students in another prayer group declared to the murderer, automatically, “We forgive you.” The horrified author of the article called their forgiveness “the sin of forgiveness.”
"This expression may be surprising for the reader, but the occasion for an editorial about it will not be. When a horrible sin is committed—for example, when a strong person uses his strength to damage someone weaker, for example, for his own sexual pleasure—it is sin to grant automatic forgiveness to the sinner. The sin is worse when the victim is pressed to forgive the abuser immediately and automatically. This is a current example many will relate to, but the subject applies in other occasions as well. No one may grant automatic forgiveness to someone who commits a serious sin. To do so is sin."