Most of us would like to be more fruitful Christians. Most of us would also like to be less vulnerable to the attacks of the evil one. At first glance these may seem to be unrelated topics, but the Bible clearly reveals that an unfruitful life is a life vulnerable to the devil's schemes, temptations and attacks, and that the fruit of the Holy Spirit forms a spiritual wall to defend us against our spiritual enemies. This study teaches how to build a strong spiritual house, in obedience to Jesus Christ, that will stand when struck by the torrents of this life. The applications extend from the walls of the individual to the walls of the Church body. In fact, this is a call to the Church to be revived and restored.