One of the many...
Spiritual wellness is most important to development because the spirit lasts forever. Through physical harmony you can achieve physical comforts, which are temporary. Through mental harmony you can achieve joy and happiness, which are also temporary. Through harmony of the spirit (soul) you can find peace. Spiritual harmony lasts forever.
Mental and physical illnesses are relatively easy to identify. Spiritual illnesses are more difficult to recognize. To heal spiritual illnesses one must purify the soul.
Purifying the spirit (soul) is the key to harmonizing the mind, body and spirit. Practicing Nae Gong (Moo Doe) meditation is one way to purify the mind, body and spirit, and to build a good foundation of Chung Doe. Once purified, you can achieve in life whatever you wish. A purified soul is a path to connect with the higher power (God).