In verse 3 Paul says, “Being diligent to keep the oneness of the Spirit in the uniting bond of peace.” The oneness of the Spirit is the Spirit Himself. To keep the oneness of the Spirit is to keep the life-giving Spirit. If we act apart from the Spirit, we are divisive and lose the oneness. If we stay in the life-giving Spirit, we keep the oneness of the Spirit.
To walk worthily of God’s calling, that is, to have the proper Body life, we first need to care for the oneness. This is crucial and vital to the Body of Christ. Strictly speaking, oneness differs from unity. Unity is the state in which many people are united together, whereas oneness is the one entity of the Spirit within the believers, which makes them all one. This oneness is a person, Christ Himself, who is the Spirit dwelling within us. It is similar to the electricity flowing within many lamps, making them all one in the shining. In themselves, the lamps are separate, but in the electricity they are one.
Christ abolished on the cross all the differences that were due to ordinances. In so doing, He made peace for His Body. This peace should bind all believers together and should thus become the uniting bond. The uniting bond of peace is the issue of the working of the cross. When we remain on the cross, we have peace with others. This peace becomes the uniting bond in which we keep the oneness of the Spirit.
Verse 4 says, “One Body and one Spirit, even as also you were called in one hope of your calling.” The Body is mentioned before the Spirit because the oneness among us is related to the Body and is for the Body. The reason we need to keep the oneness is that we are all one Body.
The Spirit as the oneness of the Body of Christ is the essence of the Body. Without the Spirit, the Body is empty and has no life. The Body here is the Body of Christ, and the essence of the Body of Christ is the Spirit. Hence, the Body and the essence of the Body are one. It is impossible for the Body of Christ to have more than one essence. The unique essence of the Body is the Spirit.
The Spirit is the essence and substance of the Body. Therefore, the church as the Body of Christ must be essentially and substantially the Spirit Himself. If there is no Spirit, there is no Body; apart from the Spirit, all we have is a human congregation. Without the Spirit, there is no substance of the church; without the Spirit, the church is merely a social organization. The church must be one Body with the Spirit as its substance.
The Spirit is not only for the Body but also in the Body. The Spirit is in the Body, not just in individual members. First Corinthians 12:13 says, “In one Spirit we were all baptized into one Body, whether Jews or Greeks, whether slaves or free, and were all given to drink one Spirit.” This verse reveals that the one Spirit is not only the essence of the Body but also the life and the life supply of the Body. Without the one Spirit, the Body would be empty and lifeless.
Moreover, 1 Corinthians 12:13 indicates that one Spirit is wrought into us and constituted into our being in order that we may be constituted into one Body. The Body is the constitution of the one Spirit, and the one Spirit has been wrought into the being of the one Body. Eventually, because the Body is the constitution of the one Spirit, we can say that the one Body is one with the Spirit.
The Spirit in Ephesians 4:4 refers to the pneumatic Christ, the all-inclusive Spirit who is within the Body and gives life to the Body. According to 1 Corinthians 12:13, the one Body came into existence through the baptism of this all-inclusive Spirit. Having been baptized in one Spirit, we must proceed to drink of this Spirit. This indicates that the existence of the Body depends on the all-inclusive life-giving Spirit. Furthermore, the Body continues to exist through our drinking of this Spirit. By our drinking the life-giving Spirit, our inward being becomes mingled with the one Spirit; this mingling of the Spirit as the processed Triune God with His chosen people as the members of the Body is the oneness of the Body of Christ.
To build up the Body of Christ is to have the Spirit wrought into us and constituted into our being in order to saturate every part of our being, making us one with the Spirit. The Body is the constitution of the divine Spirit. This indicates that the one Body and the one Spirit are not two separate entities. Rather, the one Body is one with the Spirit, and the one Spirit is one with the Body. For this reason, there must be no division in the Body. Since the Spirit is one, there can be only one Body.
The Spirit as the essence of the Triune God has become the essence of the one Body. The essence of the Body of Christ is the Spirit, who is the consummation of the processed Triune God (John 7:39; Rev. 22:17a). The essence of the Body of Christ, containing the divinity of the Triune God, has the capacity to supply the divine life (Phil. 1:19); the essence of the Body of Christ, containing the excelling humanity of Jesus, has the capacity to supply this excelling humanity (Acts 16:7); the essence of the Body of Christ, containing the all-inclusive death of Christ, has the capacity to put to death the negative things (Rom. 8:13); and the essence of the Body of Christ, containing the surpassing resurrection of Christ, has the surpassing capacity of resurrection (Phil. 3:10).
The Spirit as the reality of the Triune God is also the reality of the Body of Christ. The reality of the processed Triune God is the consummated Spirit of reality (John 14:17; 15:26; 16:13; 1 John 5:6). The Spirit of reality makes everything of the processed Triune God a reality in the Body of Christ (John 16:13-15); the Spirit of reality makes all the riches of the Triune God real to the Body of Christ. Without the Spirit, there is no Body of Christ, no church.
The Spirit is the inward essence and the expressed reality of the Body of Christ. The Spirit is the secret to all that the Triune God is to the Body of Christ. This Spirit now dwells in our regenerated spirit and is joined to our spirit as the mingled spirit (Rom. 8:9-11; 1 Cor. 6:17). Therefore, we must turn to our spirit, set our mind on the spirit, and walk according to our spirit. When we live in the mingled spirit, we will be able to live out the Body of Christ and become His corporate expression.