Question—What constitutes "the church, which is His body," and has it now a corporate existence on earth?
Answer—the unfolding of this blessed truth, "the mystery of Christ," was committed to the Apostle Paul. It is in his letters we shall find instructions concerning it. Eph. 4:4 declares, "There is one body, and one Spirit, even as ye are called in one hope of your calling."
This began at Jerusalem when the promise of the Father was given; the Holy Ghost came upon the disciples in the upper room on the day of Pentecost. (John 14:16, 17; Acts 2:32, 33, 1-4.) It could not take place before (John 7:39). It was then that the baptism of the Holy Spirit took place, and thus formed them into "one body" (1 Cor. 12:13). From that time on God has been gathering into one the children of God that were scattered abroad. The Jews, the Samaritans, and the Gentiles, all who were true believers, were brought into that one body by the gift of the Holy Spirit dwelling in them. Acts 10:44, 45 and 11:15-17 is the bringing in of the first Gentiles into the body of Christ.
This truth is not spoken of in the Old Testament, nor was it given out till Paul received it from Christ in glory; then it was made known for the obedience of faith (Rom. 16:25, 26).
It was God's purpose concerning His beloved Son to give Him a body and a bride—companions to share His glory. And all who are called during this present period of grace, and know Christ to the salvation of their souls, both of Jews and Gentiles, will inevitably have this place in glory with Him.
This was God's purpose before the foundation of the world, and is now being carried out. "Christ... loved the church, and gave Himself for it" (Matt. 13:45, 46; Eph. 5:25) when it existed only in the purposes of God. It was God's great thought for His Son to have one in whom His affections rested, and who would be through grace alone, the display of His glory through all eternity (Eph. 3:21).
In the meantime the members are being called out—that is, set apart—and cleansed by the washing of water by the Ward, fitted for Him as in the picture in Gen. 24—Rebekah was fitted for Isaac (Eph. 5:26); and then when the last member is brought in, He will tarry no longer. We shall be caught up, and He will present her to Himself without spot or wrinkle, or any such thing, holy and without blemish (v. 27). In Eph. 1:23 we see her in the glory—the fullness of Him that fills all in all—the bride of the Second Man, displaying His glory.
Now on earth the living Christians are spoken of as the body of Christ, and it is always complete. In Rom. 12:4 and 5 we see the members working together, each one according to the grace given, ministering according to its faith. In 1 Cor. 12 it is described in its functional activity. It is plainly here on earth and now. There is no preaching of the gospel in heaven, no suffering for Christ there; all this is on earth.
If we were judging by the frequent behavior of Christians, we might conclude that the body of Christ is not on earth, or just a theory and not a fact; but the Word of God declares, "There is one body." Outwardly neglected, and scattered into denominations, we do not see it as such. Christians, some in ignorance and some in self-will, refuse to obey the truth, or neglect it; but there the word stands, "There is one body, and one Spirit, even as we are called in one hope of your calling," thus giving us all the privilege, and putting on us the responsibility of maintaining"- the unity of the Spirit in the bond of peace. We are not asked to keep the unity of the body. The Holy Spirit has formed the body, and maintains it by His presence, uniting every believer to Christ in glory, so that till the Lord comes for His Church, it is ever true, "There is one body," and faith will act upon it, seeking to maintain the unity of the Spirit in the bond of peace.
There is no scriptural way to gather together and to take the Lord's supper except as members of the body of Christ, in the acknowledgment of this truth. (1 Cor. 10:16, 17 proves this.)
The Lord’s Supper is the external expression of this unity. We being many are one bread (or loaf), one body, for we are all partakers of that one loaf.
In the cup we see redemption. In the loaf, unity of the body. We, therefore, own every true believer as a member of that body of Christ, only in the last days we need carefulness to distinguish those who truly call on the Lord out of a pure heart. At the first, all who believed were together. Now, there are sad divisions, but the "one body" remains.
The first mention of the Church in Scripture is in Matt. 16:18 where the Lord calls it "My church." It is composed of living stones, built upon Christ the Rock, in eternal security from the power of death. 1 Pet. 2:5 describes these living stones as a holy priesthood, offering up spiritual sacrifices acceptable to God by Jesus Christ—each one a purged worshiper. They are the same saints that compose the body of Christ, here seen as a worshiping company.
Where men are the builders, the professing church is looked at in responsibility, and there it includes all, both saved and unsaved, who have been baptized (1 Cor. 3:10-17; Eph. 4:5; 2 Tim. 2:19-22; 3:2-5; 1 Pet. 4:17; Jude; Revelation chapters 2 and 3). These could not represent the body of Christ, as it includes only believers.