When you become a Christian, the Holy Spirit comes in you and will never leave you. You become a haunted house because you are filled with the Spirit. Although you have authority in the Spirit, when addressing the evil demons in this world, we must rely on the authority of Jesus Christ to be on our side. There are plenty of evils in this world, yet God has chosen us as His followers to dwell in us in order so that we may become more like Him and be able to fight against the powers of darkness. Once the Spirit dwells in us there is nothing that can ever separate Him from us.