For both individuals, such an action can help with spiritual awakening. From the point of view that we do bad stuff, we can see later the difference between light and dark. We may realize how it is without the light because we have experienced it. On the other side, when someone is doing the wrong to us, we can forgive and pray for that person to find his or her path. So, both beings can take advantage and progress if there is a will. However, that does not mean they automatically will do so. We may fight and refuse forgiveness, and that will bring bad Karma to be paid.