The truth is parts of us are dying all the time. You probably just lost half a million or so cells just reading this sentence. We all lose about 100,000 cells per second. Fortunately, just as many cells are being reproduced in a healthy body. Healthy bodies have this constant cycle of dying cells and rebirth of new ones. Some scientists say that we are regenerated every seven years, which is an enormous relief to me. Apparently, cells that don't die off in the normal cycle are a real problem. These cells are related to diseases like cancer and become problematic because they get in the way and block healthy development of the body.
This is true in the spiritual and emotional life as well. "Those who love their life will lose it, but those who love their lives for my sake will save it." (Luke's words are better here because there is so much more at stake than heaven in these words.) Our failure to let go and let some things die is a primary spiritual disease, for new life can't come without some death. The failure to forgive leads to death of relationship while anger and bitterness ravage the spirit like a cancer. Holding on to regrets strangles hope before it can lift us to new life. Trying to control events and other people leads to frustration, excessive stress, and exhaustion. Forgiveness and letting go of control are spiritual exercises in the art of dying so that new life may abound.