A merry [rejoicing] heart doeth good like a medicine. Proverbs 17:22. OFC 54.1
The relation that exists between the mind and the body is very intimate. When one is affected the other sympathizes. The condition of the mind affects the health to a far greater degree than many realize. Many of the diseases from which men suffer are the result of mental depression. Grief, anxiety, discontent, remorse, guilt, distrust, all tend to break down the life forces and to invite decay and death. OFC 54.2
Disease is sometimes produced, and is often greatly aggravated, by the imagination. Many are lifelong invalids who might be well if they only thought so.... OFC 54.3
Courage, hope, faith, sympathy, love, promote health and prolong life. A contented mind, a cheerful spirit, is health to the body and strength to the soul. OFC 54.4
Gratitude, rejoicing, benevolence, trust in God's love and care—these are health's greatest safeguard. OFC 54.5
The power of the will and the importance of self-control, both in the preservation and in the recovery of health, the depressing and even ruinous effect of anger, discontent, selfishness, or impurity, and, on the other hand, the marvelous life-giving power to be found in cheerfulness, unselfishness, gratitude, should also be shown. OFC 54.6
There is a physiological truth—truth that we need to consider—in the scripture, “A merry [rejoicing] heart doeth good like a medicine.” OFC 54.7
The true principles of Christianity open before all a source of inestimable happiness. OFC 54.8
We should encourage a cheerful, hopeful, peaceful frame of mind; for our health depends upon our so doing.12My Life Today, 151. OFC 54.9