When did the church begin? Many Christians locate the birthday of the church at the miracle of Pentecost that is recorded in Acts 2. Others rightly insist that the origin of the church lies deeper in the Old Testament. In Christ, the church is the "offspring of the woman" described in Genesis 3:15, and it develops organically throughout the Old Testament in the unfolding of God's covenants with His people as Abraham is called out of Ur and the nation of Israel is established at Sinai. As R.B. Kuiper described it, old covenant saints were saved by the Christ of prophecy and new covenant saints by the Christ of history. Just as Christ is the one mediator between God and humanity, so there is one covenant of grace, one plan of salvation, and thus one people of God.
Yet to locate the historical origin of the church either at Eden or at Pentecost may obscure the deeper truth that the church's origin lies in God's eternal counsel. Reformed Christians confess that the decrees of God are "his eternal purpose . . . whereby, for his own glory, he hath foreordained whatsoever comes to pass" (WSC 7). At the heart of this decree lies a "covenant of redemption" (or a "counsel of peace") wherein the triune God manifests His glory by saving a people through the mediation of Jesus Christ.
Here is where the eternal origin of the church comes into focus. Under this eternal, intra-Trinitarian covenant, the Father plans redemption and sends the Son in order to save His people. As the Son accomplishes what He set out to do (in His obedience even unto death), the Father rewards Him by appointing Him heir of all things and forms a church, a people for His inheritance. The Father and the Son send the Spirit to testify to Christ and apply Christ's redemption to the hearts of Christ's people, making them joint heirs with Christ.
It is proper, therefore, to acknowledge that the church originated in eternity past. Several consequences ensue from the eternal and covenantal origin of the church. First, the elect in Christ are not isolated individuals; they are a people, an organism that reflects God in His Trinitarian fullness. Thus, as Herman Bavinck writes, "The covenant of grace does not leap from individual to individual but perpetuates itself organically and historically. . . . It is a covenant from generations to generations." The churchly focus of God's electing grace will guard us from the prevailing individualism of our age; we cannot be united to Christ if we refuse to be united to His people.
This truth underscores both the continuity and discontinuity of the church in its historical expression. It is one people, with progress and development in covenantal administration. And in its wandering in the wilderness of this present age, the church remains a people "on the way"—we are not home yet, and we are still called to persevere in our worship and service to our God in our pilgrimage. Elected and redeemed, the church is still being gathered and perfected. Distinguishing the church from all eternity from the church in history serves to guard against "overrealizing" our eschatology (doctrine of last or ultimate things). The church will be perfected only in glory.
The eternal counsel of peace highlights the Son as the "surety" of the covenant, and so we find in Christ alone the hope and security of the church. "All that the Father gives to me will come to me," Christ assures us, "and whoever comes to me I will never cast out" (John 6:37). The "peace" of this covenant is purchased for us according to Christ's priestly office, maintained and defended by His kingly office, and revealed by His prophetic office. Because the God who decrees the church is the same God who sustains the church, the future of the church is in God's hands. This encourages us to see the church with the eyes of faith. It is bigger and stronger than its frail and precarious human expression suggests. Though despised and disparaged by this world, the church is the apple of God's eye (Zech. 2:8) that will prevail against all of her enemies.
Finally, the eternal origin of the church provides our assurance of faith. Commenting on God's words in Jeremiah 31:3 ("I have loved you with an everlasting love; therefore I have continued my faithfulness to you"), Geerhardus Vos famously wrote, "The best proof that He will never cease to love us lies in that He never began." That everlasting love finds expression in the covenant of redemption. As the Heidelberg Catechism beautifully puts it, the church is "a community chosen for eternal life and united in true faith. And of this community I am and always will be a living member" (Q&A 54).