“Keep thy heart (or imagination) with all diligence, for out of it are the issues of life.” (Prov. 4:23.) homepage quote
This means that what man images, sooner or later externalizes in his affairs. I know of a man who feared a certain disease. It was a very rare disease and difficult to get, but he pictured it continually and read about it until it manifested in his body, and he died, the victim of distorted imagination.
So we see, to play successfully the game of life, we must train the imaging faculty. A person with an imaging faculty trained to image only good, brings into his life “every righteous desire of his heart”—health, wealth, love, friends, perfect self-expression, his highest ideals.