On this day fifteen years ago, the United States was attacked by Islamist extremists. The images of that day, especially of the Twin Towers imploding and collapsing, are forever burned in the memory of all who witnessed them in person or on television.

It was another “day of infamy” for the world’s strongest superpower and for its citizens, who were unaccustomed to such acts of terrorism.

It seems that no American who experienced that day will ever forget the attack, and so as a consequence they will always remember what they were doing on the morning of September 11, 2001. From teaching class, to running errands, to sleeping in, to starting their day at work, that morning’s activities will oddly never be forgotten.

This scar of terrorism and the national flashback it compels raises some important spiritual questions about bad memories in general and about healing in particular. How is a person to deal with recurring memories that harm and debilitate them? Is healing and restoration possible?

The Christian spiritual tradition has always asserted the possibility of healing, especially from haunting or troublesome memories. As the Christian faith points to the passion, death, and resurrection of Jesus Christ, it teaches that evil and suffering (and the memories born from them) do not define reality and they do not have to possess the last word in a person’s life or in human history.

As torturous as the Lord’s passion and death were, they were fulfilled, elevated, and sanctified by the glorious rays of the resurrection. When accepted in faith, this power of the resurrection offers hope to any person of good will who is looking for healing and peace.

As hope is given by faith in the resurrection, it develops and matures beyond a simple wish for the best state of affairs in this life and instead grows toward an expectation of eternity and perpetual happiness in the afterlife.

Pope emeritus Benedict XVI described this process when he wrote: “Day by day, man experiences many greater or lesser hopes, different in kind according to the different periods of his life. Sometimes one of these hopes may appear to be totally satisfying without any need for other hopes. When these hopes are fulfilled, however, it becomes clear that they were not, in reality, the whole. It becomes evident that man has need of a hope that goes further. It becomes clear that only something infinite will suffice for him, something that will always be more than he can ever attain.”

This hope of eternity is not a fantasy or superstition but something that flows from a person’s own transcendental nature, from her very own soul and life of faith. And so, the Letter to the Hebrews defines faith as “the assurance of things hoped for, the conviction of things not seen.”

In this way, hope provides the believer with a more expansive and holistic experience of life. The horizontal array of struggles and bad memories are balanced and broadened by an openness to a vertical perspective and understanding.

Such a universal approach can begin to free a person’s mind and heart of memories that have become absolutized by horror or shock and which try to enslave a person, her feelings and her grasp on life into a realm of on-going darkness.

Hope identifies all the memories of a person’s life, good and bad, and shows her the full narrative of her existence while placing everything within the light of eternity. This broadening gives a person a greater freedom and context with which to see and view her life. Hope shows the person that her life is not defined by one wound or heartache.

In expanding a person’s perspective, hope also allows her to see the saints in heaven united with her and to recognize others in this life who have endured similar sufferings. This observation leads her to mutual empathy and to genuine human solidarity. Hope allows the person to see that she does not suffer alone.

The bright rays of hope given by faith in the resurrection, therefore, have the power to thaw and soften the experiences of life that have been frozen in a person’s recollection and which seek continually to disturb and torment her.

In this way, the burden of traumatic memories can be lightened as hope begins to purify and heal the mind and heart of a person and of a nation. But hope, enriched and empowered by faith, is needed for such healing to fully happen.