The greatest power over a person can be gained not by force of action, but by persuasion of belief. The more a person believes in a deception, the more they will use their own free will to sponsor that belief. Thus, the battle over hearts and minds has more potential for power than any other battle.
Heavenly Father also battles for our hearts and minds through persuasion. But if we are persuaded to believe truth, our choices are guided by correct knowledge, making us truly free. Contrarily, when our choices are guided by incorrect knowledge, we are simply being used by the Deceiver.