Much of Christianity is weak and powerless because it has not received a revelation from God of the Corporate Body. Many people choose to live in their natural human existence because of the expense of the Cross of Christ. They have a mental concept of what it means to be a member of the Body of Christ, but they lack the power of the One New Man who is the only spiritual man in all the earth. We are either a member of the spiritual man, or we are natural.
You cannot attain an understanding of the Corporate Body through much studying because it takes a revelation of the Holy Spirit to reveal the riches of the glory of His inheritance in the saints.
So many people are sentimentally attached to a natural system of Christianity that they refuse to bear His reproach and go forth unto Him outside the camp. While they live within the confines of the camp, they will never receive a revelation of Him Who is without. When Moses came down from receiving the commandments, Israel was worshipping the golden calf, In response to this demonstration of idolatry, Moses pitched the tabernacle of the congregation outside the camp. Christ sees thousands worshipping something that they can see or feel that symbolizes God but has no Cross. He has demonstrated against this idolatry. He has pitched His tabernacle, His One New Man, outside the camp. The only way in is through the Cross.