In its universal aspect the church is the universal Body of Christ to be His fullness. In Ephesians 1:22-23 Paul speaks of "the church, which is His Body, the fullness of the One who fills all in all." This is the church in its universal aspect, for Christ has only one Body, which is unique in the universe. Christ's universal Body is His fullness, His expression.
In addition to knowing the church, we need to know the Body of Christ.
The Body of Christ is the mystery of Christ (Eph. 3:4). The mystery of God in Colossians 2:2 is Christ; the mystery of Christ in Ephesians 3:4 is the church. God is a mystery, and Christ, as the embodiment of God to express Him, is the mystery of God. Christ also is a mystery, and the church, as the Body of Christ, is the mystery of Christ. This mystery is God's economy, which is to dispense Christ, as the embodiment of God, into God's chosen people in order to produce a Body to be the increase of God's embodiment in Christ so that God may have a corporate expression.
The Body of Christ is the fullness of Him who fills all in all (Eph. 1:23). It is the universal expression of the all-inclusive and all-extensive Christ. The Body as Christ's fullness is the fullness of Him who fills all in all. Christ, who is the infinite God without limitation, is so great that He fills all things in all things. Such a great Christ needs the Body to be His fullness for His complete expression.
The Body of Christ is the organism of the Triune God, constituted with the Triune God and the believers (Eph. 4:4-6). The divine life is a substance, the Triune God, and the organism of the Triune God is the visible expression of this substance. Therefore, as the organism of the Triune God, the Body of Christ is altogether organic and is absolutely of life. An illustration of this organism is found in John 15—the vine with its branches. The vine is developed and enlarged through its branches. This is a picture of the Body of Christ as the organism of the Triune God, an organism that grows with the riches of the Triune God and expresses the divine life.
The organism of the Triune God, the Body of Christ, is an issue of the Divine Trinity; it is an issue of the Father as the source, the Son as the course, and the Spirit as the flow. Furthermore, the Body is constituted with the Triune God and the believers. In this constitution the Father is the source, the Son is the element, the Spirit is the essence, and the believers, God's redeemed and regenerated people, are the outward framework. The Father as the source, the Son as the element, and the Spirit as the essence are all in the outward framework.