"He who would accomplish little must sacrifice little; he who would achieve much must sacrifice much; he who would attain highly must sacrifice greatly. He who would be useful, strong, and happy must cease to be a passive receptacle for the negative, beggarly, and impure streams of thought; and as a wise householder commands his servants and invites his guests, so must he learn to command his desires and to say, with authority, what thoughts he shall admit into the mansion of his soul."