Matthew 5:39 Jesus says, "But I tell you not to resist an evil person. But whoever slaps you on your right cheek, turn the other to him also."
Hit me and ill hit you back has become an immature thing of the past. Something we've taught our kids because it was taught to us, but we now have the responsibility as followers of Christ to show people grace. Though it may seem like someone is getting over on you, or your backing down, stay positive, be forgiving, you will be blessed for keeping a Christ like attitude. If every time we hurt God by doing things we have no business or doing things that contradict the reasons Jesus died for us and He hurt us back. We'd be in a crucial state of continuous, unbearable, hurt and pain, but He forever shows us this everlasting and undeserved grace that gives us the opportunity to forgive and be forgiven. Think about that when you want to get back at someone for any reason. God knows and sees all. You cant get back at them like He can anyway. So be blessed in knowing Gods got your back and having grace is a privilege to give and receive.