The universal law of karma ... is that of action and reaction, cause and effect, sowing and reaping. In the course of natural righteousness, man, by his thoughts and actions, becomes the arbiter of his destiny.
Paramahansa YoganandaProper visualization by the exercise of concentration and willpower enables us to materialize thoughts, not only as dreams or visions in the mental realm, but also as experiences in the material realm.
Paramahansa Yogananda