When one hears the word meditation, it conjures an image of Maharishi Yoga talking about finding a mantra and striving for nirvana. The purpose of such meditation is to empty oneself. [Satan] is happy to invade the empty vacuum of your soul and possess it. That is why people serve Satan without ever knowing it or deciding to, but no one can be a child of God without making a decision to surrender to him. Beware of systems of spirituality which tell you to empty yourself. You will end up filled with something you probably do not want.