The soul is a God-shaped void. If I would carry it further, I would say your soul is a God-shaped garment, like a glove shaped to fit your hand. God cannot enter, because it is full of rubbish. Try putting a lot of junk in the glove sometime and then try placing your hand into it; you cannot do it. That glove must be empty before a hand can go into it. The heart must be empty before God can enter.