Fred Luskin, a psychologist from Stanford University, once wrote: "Holding on to hurts and nursing grudges wears you down physically and emotionally. Forgiving someone can be a powerful antidote. It is about breaking free from the person who wronged us." Similarly, Charlotte van Oyden Witvliet, a collegiate psychology professor, agreed. She conducted a study with 71 volunteers that showed people who don't forgive experience "steep spikes in blood pressure, heart rate and muscle tension." Forgiveness, Witvliet found, "helps people to remain calm. Forgiveness isn't about condoning what happened." Jesus taught this truth about 2,000 years before either of the latter two professors made the foregoing findings. In Luke 17:4, Jesus said: "And if he sins against you seven times in a day, and comes back to you seven times, saying, 'I repent,' you must forgive him."