This is now the first post in a section on the Church in my ongoing series, theology in bullet points. The first unit in this series had to do with God and Creation (book here), and the second unit was on Christology and Atonement.
We are now in the third and final unit: The Holy Spirit and the Church. The first set of posts in this final unit on the Spirit and the Church was on the Holy Spirit.
In Christ, the Spirit creates the Church.
1. The Church is the body of Christ in which the Spirit dwells. It consists of all those in Christ since Jesus rose from the dead. It was made possible through Christ's blood, inaugurated in his resurrection, and implemented on the Day of Pentecost, when the Spirit was sent forth in his fullness. The Church consists of all those who have received the Holy Spirit since then, in all times and places, who have persisted in faithfulness to the end in the past or who continue to persist in faithfulness today.
The Church is the "communion of saints." It is the people of God in the new covenant, just as the faithful within Israel were the people of God in the old covenant. But these are not two peoples but the one people of God, along with all who call upon the name of the Lord in all times and places according to the light they have.
2. Christ is the rock on which the Church is built. Matthew 16:19 may give the keys of the kingdom to Peter, and Peter may have been a rock in the early church. But the reason for this exchange is Peter's acknowledgement that Jesus is the Christ (16:18). This is the real rock on which the Church is built. The gates of death cannot prevail against the Church because Jesus has risen from the dead and been enthroned as king.
The death and resurrection of Jesus are the foundation of the new, spiritual temple of God, which is the Church (1 Cor. 3:11). From a slightly different perspective, Jesus is the cornerstone of God's house, the Church, with the apostles and prophets as the foundation (Eph. 2:20). Christ's death makes it possible for the Church to be a bride of "splendor, without a spot or wrinkle or anything of the kind" (Eph. 5:27).
Those who are in the Church are "in Christ." They are baptized into his death and rise with him to new life, united with him in both his death and resurrection (Rom. 6:4-5). We have been crucified with him and remain crucified with him (Gal. 2:20). The life we now live, we live in his faithfulness to death.  And we live it by faith, trusting in God. 
In Christ, we--the Church--are all children of God (Gal. 3:26). In our baptism, we have put on Christ as our clothing (3:27). We have all become the children of Abraham through faith (3:29), just as the biological children of Abraham are only truly his children on the basis of faith (cf. Rom. 3:30).
In Christ, there is no distinction between races, like Jew and Gentile (Gal. 3:28). In Christ, there is no distinction between those of different worldly status, like slave and free. In Christ, there is no distinction between male and female. The consequences of Eve's sin (Gen. 3:16), at least in so far as they exist in the Church, are wiped away by the blood of Christ.
The Church thus knows no hierarchy or distinction based on race, status, or gender. The Spirit, who creates the Church, is the great equalizer. We all have the same body, the body of Christ.
3. The Church was born by the Spirit on the Day of Pentecost. The death and resurrection of Jesus made the Church possible, but it is the Spirit that has created the Church.
"Anyone who does not have the Spirit of Christ does not belong to him" (Rom. 8:9). In that sense, technically, there were no Christians before the Day of Pentecost, for it was not until Pentecost that the Spirit came in full force.  The Day of Pentecost is thus the birthday of the Church. 
As presented earlier in this series, the Holy Spirit not only prepares us for the Church. The Holy Spirit purifies our sins as we enter the Church (Acts 15:9). The Holy Spirit is the "seal" of God's ownership over us (1 Cor. 1:22). The Holy Spirit gives witness to our spirits that we are the children of God (Rom. 8:16).
Within the Church, the Holy Spirit creates unity. The Holy Spirit leads the Church into truth. The Holy Spirit empowers the Church for mission and service.
The Church is "in Christ." It is the body of Christ, in which the Spirit of Christ dwells. All those who have the Holy Spirit are in the Church.
Next week: E2. The Church is both visible and invisible.
 Although there remains significant debate, many scholars including myself believe that the expression, "the faith of Jesus Christ" in Romans 3:20 and Galatians 2:16 had a first sense of "the faithfulness of Jesus Christ," referring to his faithfulness to death (cf. Phil. 2:8). By the one man's act of obedience, many will be made righteous (Rom. 5:19).
 Unlike those who see Paul's rhetoric as an either/or, I am more and more convinced that he uses both images, starting with reference to the faithfulness of Jesus but ending with the importance of our faith. The very way the Greek of Galatians 2:20 itself is worded suggests such a double entendre. "The life that I now live I live by faith," it begins. Then Paul tags on, "the [faith] of the Son of God, who loved me and gave himself for me."
 There are no doubt those who would suggest that Acts' depiction of the Day of Pentecost was somewhat of an artistic and heavily theological presentation of history. Whether this claim would prove to be correct or not, it would not thereby undermine the theology of Acts 2. Clearly it was the understanding of the early church that the existence of the Church was based on the presence of the Holy Spirit in the lives of all believers and that this possibility followed from Jesus' death and resurrection.
 For the American holiness movement, Pentecost represented "entire sanctification," a moment of full purity and power. In this scenario, the disciples were already Christians, but they were not yet entirely sanctified, which happened on the Day of Pentecost. There is a certain power to this interpretation, for it provides a model for believers to come to a moment of decision where they surrender their whole lives to God and let him fully take over and fully defeat any power of Sin that might remain over their lives.
However, the book of Acts itself does not seem to think of this event in this way. In the imagery of Luke-Acts, the Day of Pentecost is the fulfillment of John the Baptist's promise in Luke 3:16 that Jesus would baptize with the Holy Spirit, something that could not take place until after Jesus had risen from the dead (cf. John 16:7).
In the end, we lose an incredibly important theological point of the New Testament about the very essence of the Church and the nature of our entrance into the Church as individuals if we do not read passages like Acts 2, 2 Corinthians 1:22, 5:5, and so forth as initial events.