According to the New Testament, the oneness of the believers, or of the church, is mysterious, for it is intimately related to the processed Triune God. John 17:21-23 indicates that the believers are to be one in the Triune God just as the Father is in the Son and the Son is in the Father. By being in the Triune God, the believers are one. Furthermore, John 17:22 says that the glory the Father has given to the Son has been given by the Son to the believers so that they may be one even as the Father and the Son are one. Then verse 23 goes on to speak of being perfected into one. When we believed, we entered into this mysterious oneness. Now we must go on to be gradually perfected into this very oneness.
In Ephesians 4:4-6 Paul lists seven aspects of oneness: one Body, one Spirit, one hope, one Lord, one faith, one baptism, and one God and Father. These verses also show the mysterious mingling of the Triune God with the Body of Christ. This mingling is the oneness of the believers. The Spirit in verse 4 is no doubt the compound, all-inclusive Spirit who is within the Body and gives life to the Body. According to 1 Corinthians 12:13, the Body came into existence through the baptism of this all-inclusive Spirit. Having been baptized in one Spirit, we must go on 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. Anything we drink becomes mingled with our inward being, with our blood and with the very fiber of our organic tissue. It is the same with the life-giving Spirit.
In Ephesians 4:5 Paul puts together the one Lord with the one faith and the one baptism. We get into the Lord through faith and baptism. To have faith in the Lord means to believe into Him. Of course, to be baptized into Him is to be put into Him. When we believed into Him and were baptized into Him, we became one with Him; that is, we were mingled with Him.
In verse 6 Paul says, "One God and Father of all, Who is over all and through all and in all." The one God and Father is over all objectively, through all in a way that is partly objective and partly subjective, and in all subjectively. Hence, the Spirit is mingled with the Body, the Body is in the Lord, and the Father is over all, through all, and in all. This is a picture of the mingling of the Triune God with the Body of Christ. In this oneness we have the one hope, the hope of our coming glorification.
This oneness is altogether different from the oneness in today's Christianity, which is a mere oneness of addition. Such a oneness of addition can also lead to subtraction. The oneness revealed in the Bible is the mingling of the processed Triune God with His chosen people. Hence, the oneness in the Scriptures is a mingling of persons, a mingling of the divine Person, the Triune God, with human persons who believe in Christ. The Triune God who is mingled with us has passed through the process of incarnation, human living, crucifixion, and resurrection. That genuine oneness referring to such a marvelous mingling is the clear revelation in John 17 and Ephesians 4.