Saint Peter, in Acts chapter 2, preached what might be considered the first Lutheran sermon. He properly distinguished law and Gospel, first showing the gathered crowd their sin, then proclaiming salvation by grace through faith for the sake of Christ.
“Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, ‘Brothers, what shall we do?’ And Peter said to them, ‘Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself.’ And with many other words he bore witness and continued to exhort them, saying, ‘Save yourselves from this crooked generation.’ So those who received his word were baptized, and there were added that day about three thousand souls.
And they devoted themselves to the apostles’ teaching and fellowship, to the breaking of bread and the prayers.” [Acts 2:37-42 (ESV)]
So on Pentecost, Saint Peter and the Apostles defined the church. Our Lutheran Confessions, specifically the Augsburg Confession article VII, defines the church: “Also they teach that one holy Church is to continue forever. The Church is the congregation of saints, in which the Gospel is rightly taught and the Sacraments are rightly administered. And to the true unity of the Church it is enough to agree concerning the doctrine of the Gospel and the administration of the Sacraments. Nor is it necessary that human traditions, that is, rites or ceremonies, instituted by men, should be everywhere alike. As Paul says: One faith, one Baptism, one God and Father of all, etc. Eph. 4:5-6.”
In the second chapter of Acts we see this played out. 3,000 people were added to the roles of the church in Jerusalem through baptism. We believe, teach, and confess that baptism is a sacrament, one of the means by which the Holy Spirit creates faith which holds to the promises of God. Thus baptism is God’s work, done through the hands of the pastor (or layman, in the case of an emergency).
Peter, in his good Lutheran sermon, quoted the Old Testament — which is appropriate, for the New Testament hadn’t been written. Indeed, there is a lot in the New Testament which happened well after Pentecost. But the Old Testament is filled with Christ Jesus. The Old Testament is filled with God’s grace, love, and mercy. When we confess in the Nicene Creed, “and on the third day He rose again, according to the Scriptures,” we are quoting Saint Paul who agrees with Jesus, Himself, that the resurrection was well and truly foretold in the Old Testament. Thus the Word, the Gospel of salvation because of God’s undeserved and boundless love, shown in the sacrificial death of His Son, is also the primary means by which the Holy Spirit creates and sustains faith.
So what is the result? 3,000 people learned from the Apostles who taught the Gospel. They took the Lord’s Supper, “the breaking of bread,” which is God’s gift to the church to strengthen faith and forgive sins. They worshiped and prayed with the Apostles, and each other, growing in faith and trust in the promise of the forgiveness of sins. They even were drawn back to their baptism as they were reminded that their sins were forgiven for Christ’s sake.
So the Church is the people of God called by Him through the proclaimed Gospel, and given the gifts promised in the Gospel through the properly administered sacraments. We consider there are either two or three sacraments, depending on your definition. The classic definition says “instituted by Jesus, and tied to a physical substance, giving the forgiveness of sins.” With this definition we have baptism and the Lord’s Supper. However, we may define the sacraments as “instituted by Jesus for the forgiveness of sins,” which then includes absolution. Take your pick. Absolution may be the applied Gospel, or it may be a sacrament. Either way, your sins are declared forgiven (John 20:23).
So the church is not a building. Nor is the church a specific denomination. The Lutheran Church may go the way of the do-do bird, and the true Christian Church (God’s saints gathered around the Gospel and sacraments) still exists. That is comforting, for our hope of everlasting life is based on God’s promises, not our sinful, human institutions.
We trust that God will preserve the Gospel in its purity, and will raise up faithful men who will be His instruments to proclaim Christ as our Redeemer, while properly administering the sacraments.
Thus we pray for the church, knowing that at least a faithful remnant will remain until our Lord returns. We also pray that we may be faithful in preaching the Gospel and administering the means of grace (Word and sacrament) according to Christ’s institution. Finally, we pray that our faithful witness of the truth will be a light in this sin-darkened world, the light of Jesus Christ.