My understanding is that God will forgive whom he wants to forgive, but of us, it is required to forgive 7 X 70. This equation is symbolic to mean that we may need to forgive every time we think of the injustice that has befallen us (or the victim). I used to feel the same way. I used to ask my attorney father, "Where is JUSTICE when a criminal walks free!?" I would also ask him all of these same questions you ask above. His response was that without Mercy, there is no Justice. The two need to go together in order for each to work correctly. Throughout my life I have learned that those who offend, and we all do at some point, don't walk away unhurt. The offender is hurt, too, although we may not see it. They have to live with the consequences of their actions; whereas, through forgiveness, the victim can heal and move on. In the end, I give it up so the offender won't have control over me and I hope Karma/God/the Universe, whoever, takes care of the offender with both Justice and Mercy so that both of them can be paid in full.