"When the unclean spirit has gone out of a man, he passes through waterless places seeking rest, but he finds none. Then he says, 'I will return to my house from which I came.' And when he comes he finds it empty, swept, and put in order. Then he goes and brings with him seven other spirits more evil than himself, and they enter and dwell there; and the last state of that man becomes worse than the first. So shall it be with this evil generation."
- Matthew 12:43-45

So one needs some new spiritual furniture as it were. The question of what exactly one does, on a practical level, having been saved "by grace" and "not because of works" (Eph. 3:8-9) always seems a bit tricky to me. There is grace. There are spiritual disciplines. I'm fairly sure God's a fan of both. It's like some bizarre kind of theologically-blindfolded mental balancing act trying not to abuse one or t'other.