Forgiveness has always been equated to spiritual growth and healing, with Christianity and other religions teaching the value of not holding a grudge against others.

Doctors, however, recently found out that forgiveness may also help relieve the body from physical difficulties and treat diseases.

Dr. Michael Barry, also a pastor, conducted a research on cancer patients and found out that about 61 percent of them had trouble forgiving.

Barry, who also authored the book called "The Forgiveness Project," explained that carrying bad feeling toward another person can lead to chronic anxiety, which in turn can negatively affect the human body.

"Harbouring these negative emotions, this anger and hatred, creates a state of chronic anxiety," the doctor explained.

"Chronic anxiety very predictably produces excess adrenaline and cortisol, which deplete the production of natural killer cells, which is your body's foot soldier in the fight against cancer," he added.

Dr. Steven Standiford, chief of surgery at the Cancer Treatment Centers of America, agrees with Barry. He also believes that refusing to forgive can cause and breed illnesses.

Because of these, doctors such as Barry are now trying a new technique called "forgiveness therapy" to help alleviate the bad effects of certain diseases.

This kind of therapy involves praying and reaching out to enemies.

Jayne Valseca, who has Stage 4 breast cancer, tried forgiveness therapy and found relief not just physically but also spiritually.

"It was as if this huge ton of bricks, this weight of the world, was instantly lifted from my shoulders," Valseca shared.

Barry, for his part, said he always shares with his patients the first step in forgiveness: realising how much we have been forgiven by God.

"When a person forgives from the heart—which is the gold standard we see in Matthew 18, forgiveness from the heart—we find that they are able to find a sense of peacefulness. Quite often our patients refer to that as a feeling of lightness," the doctor said.