Intentional silence almost always feels like work.  It doesn't come naturally to most people, and there is in fact considerable resistance raised from the mind itself: "You mean I just sit there and make my mind a blank?"  Then the inner talking begins in earnest, and you ask yourself, "How can this be prayer?  How can God give me my imagination, reason, and feelings and then expect me not to use them?"  "Where do 'I' go to if I stop thinking?"  "Is it safe?"

Cynthia Bourgeault, Centering Prayer and Inner Awakening, pg. 8-9