The most precious of all possessions is power over ourselves
— 

John Locke (1632-1704) English philosopher 

If a man for example has no control over, or use of his own hand,  he cannot very well control or handle any other object . The quest for dominion in other areas of life is impossible without dominion over ourselves. For too many people, all attention is focused on outward things in their attempt to change their life outcomes.