That it may please thee to bring into the way of truth all such as have erred, and are deceived, We beseech thee to hear us, good Lord.
"To err is human" the old saying goes. Yes, but to deliberately deceive another is horribly cruel. I have known such people and I have a very hard time forgiving them. I can only place them in God's hands. I have also known those who have been on the "err" side of things because they were deceived.
It is so hard to watch a loved one go through the pain of discovering that they have been deceived; watching that loved one err time and again because they believe the lies of another. When the truth finally comes to light and the loved one realizes what has happened, you watch them go through deep embarrassment and shame for the pain they have contributed to. But there is God in all of this. When my loved one asks, "How can you forgive me after what I've done?" I simply reply, "Because God's love is unconditional."