Nothing tends more to promote health of body and of soul than does a spirit of gratitude and praise...It is a law of nature that our thoughts and feelings are encouraged and strengthened as we give them utterance. While words express thoughts, it is also true that thoughts follow words. If we would give more expression to our faith, rejoice more in the blessings that we know we have - the great mercy and love of God -we should have more faith and greater joy.
Ellen White, The Ministry of Healing, pp. 251-253
I pulled this quote from a shorter article whose author goes on to say:
Our words not only reveal our inner character; they shape it. Let your mouth be filled with praise. Let your lips express thanks to God for His goodness. Watch how praise pulverizes your discouraging feelings. Praise is one of God's mighty weapons to overcome the enemy. Praise is a weapon we cannot afford to be without.
Mark Finley, Solid Ground, p. 139
Praise. The most powerful weapon against fatigue of any kind -diet, dissertation, and life!