When the unclean spirit has gone out of a man, he passed 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 also with this evil generation. Matt. 12:43-45, RSV.
Christianity is not a negative.
No one will ever be saved by what they stopped doing.
That is the lesson Jesus teaches in Matthew 12:43-45. His closing words refer to the wayward Jewish leaders of His time. By all counts those individuals, from a human perspective, were good people. For their religion they were willing to give up almost any pleasure. They had huge lists of forbidden things that they followed in order to clean up their lives.
In a sense they had swept their house clean and put it in order. Yet a few verses earlier we learned that they were plotting the death of Jesus (verse 14). By claiming that He was inspired by the devil (verse 27), they were committing the unpardonable sin (verses 31, 32).
Yet they were good people. Went to church every Sabbath. Gave tithes fanatically. And kept away from bad things to eat. Their problem, Jesus points out, is that they had gotten rid of the nasty things in their life, but hadn't let God fill it with the positive. As a result, they now had a religious devil (or seven of them) and were worse off than ever, because there is no sin so deceptive as the sin of goodness and pride in one's religious achievements.
Those kinds of people are still with us today. I once met a sanctimonious church member who was meaner than the devil. And I even encountered a vegan that could outdo the devil.
The focal point of Christianity is not so much getting rid of the evil (although that is certainly important, even if it is only preparatory) as it is letting God's Spirit into our lives with His fruit. Not emptiness, but fullness is God's goal for each of us. Not the negative but the positive. "The fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control" (Gal. 5:22, 23, RSV).
Christianity is a positive rather than a negative. It is fullness of the Spirit rather than a mere emptiness of evil.