This is now the third post in a unit on the Holy Spirit in my ongoing series, theology in bullet points. The first section had to do with God and Creation, and the second was on Christology and Atonement.
SP3. The Spirit sanctifies the Church.
1. Those of us who live in "Western" Christianity are prone to think of our faith in individualistic terms. When Martin Luther centered Christian faith around the idea of justification by faith, he not only centered Christianity around humanity but he centered it around human individuals. John Wesley also tended to focus on salvation as the focus of Christian doctrine, with my individual salvation taking up a major part of his teaching. 
By contrast, the early church grew out of a group or "collectivist" culture, so we are not surprised to find that the Y-O-Us of the New Testament are primarily plural. In a familiar verse for Wesleyan circles, Paul does not express a desire for each individual to be "sanctified" but that the believers at Thessalonica as a whole, together, be sanctified as one body and in one spirit and be preserved blameless (1 Thess. 5:23). The correct priority within salvation and the Church is thus the collective body of Christ first and the individual believer second.
2. The Holy Spirit "sanctifies" the Church (cf. 2 Thess. 2:13). The predominant sense of sanctification is to "make holy."  To make something holy is to make it God's, to set it apart as belonging to the realm of the divine rather than the realm of the ordinary. An earlier article mentioned that to say that God is holy was tantamount to saying that God is God and thus set apart from the creation in awesomeness and glory.
The Holy Spirit sets the Church apart as God's and thus creates the Church, the collective body of Christ. The Holy Spirit is the spirit that inhabits the body of Christ, the Church. As we will see in a later article, the Church is the people of God, the collection of all those "in Christ" past, present, and future.
3. A second meaning relates to the first. When the Spirit sets apart the Church to belong to God, he purifies it. To be sure, impurity remains in the Church. The church at Corinth is sanctified (1 Cor. 1:2) and yet there are "fleshly," "unspiritual" people within it (1 Cor. 3:1). An unbelieving spouse similarly can be "sanctified," set apart as connected to God, and yet not as yet be "saved" (1 Cor. 7:14, 16).
Yet on the basis of the blood of Christ, the Holy Spirit washes the Church, like a bride being prepared for an ancient marriage. In the culture of the New Testament world, the bride was washed and presented to the husband "without a spot or wrinkle or anything of the kind" (Eph. 5:27). In the same way, the Spirit prepares the Church for Christ when he returns. The Spirit makes the Church into a "a chosen race, a royal priesthood, a holy nation, God’s own people" (1 Pet. 2:9).
4. The Holy Spirit also empowers the Church. Perhaps nowhere do we see this dynamic better than in the early chapters of Acts. In Acts 2, the Holy Spirit gives birth to the Church as the collective body of believers on the Day of Pentecost receive the Holy Spirit for the first time in a way the Spirit had never yet come in history.
The pages that follow show the effects of the Spirit on the Church. The Church is immediately empowered for witness as the apostles begin to proclaim the good news to everyone present in Jerusalem. They receive the power of tongues, which in the case of Acts 2 seems to be the ability to speak in languages that they have never learned before, so that they can speak the good news to those present.
This event of tongues is the reversal of what happened at the Tower of Babel, when God separated the people by giving them a diversity of languages. But the event of tongues on the Day of Pentecost signifies another extremely important effect of the sanctification of the Spirit--unity. The Holy Spirit brings unity to the Church in its diversity.
Ironically, the use of "tongues" later at Corinth would create a problem when individuals used it to highlight their individual gift over the unity of the congregation. Paul would attack this use of spiritual gifts as it pulled the church there toward individuality over corporate unity (1 Cor. 12-14). The church is full of individuals with different gifts from God, but the point of these gifts is to accomplish the mission of God and to edify each other.
These gifts point to the mission of God, not some individual mission I'm on. These gifts point to my service of others, not to how special I am as an individual to God or how great I am.
The Holy Spirit thus brings unity to the body of Christ. Where there is division and a dividing of the church into cliques and factions, the Holy Spirit is not behind it. Where the Holy Spirit is, there is unity. 
So the Holy Spirit incorporates us into the body of Christ, the Church, through sanctification. The Holy Spirit empowers the Church for unity and proclamation. The Holy Spirit empowers individual believers in a diverse number of ways that serve both the broader mission of God and that build up the body of Christ collectively.
5. The Holy Spirit also directs the Church and leads it to the truth. The Holy Spirit is the Spirit of truth (e.g., John 15:26). John 16:13 indicates that one of the functions of the Spirit was to lead the first disciples into all truth. And since God has given these words in Scripture to the whole Church, we can have confidence that the Spirit is still leading us into all truth.
The Spirit first gave the apostles truth to speak before there was a New Testament. They did not always agree with each other, as we see in Galatians 2. We thus see that the leading of the Spirit into truth does not always come without some conflict and debate.
The Spirit had already "hovered over" the creation of the books of the Old Testament. The Spirit had breathed into them at first and the Spirit continued to breathe into them at the time of Christ.  In the writings that would become the New Testament, the Spirit continued to breathe words to his people and through the words to later generations.
It took hundreds of years for the books of the New Testament to come together into their current form, so if we accept them as our Scripture we must also accept that the Holy Spirit continued to inspire the Church to collect these books into their current form. This action of the Spirit, again, did not come without conflict or debate. It is by faith that we believe that the Spirit approved of the way those books came together.
The Spirit continues to reveal and lead into truth. The Gospels allude to this fact when Jesus tells Peter in Matthew 16:19 that he is giving him the keys to the kingdom and that whatever Peter binds or looses on earth will already have been bound or loosed in heaven. Similarly, Jesus tells the disciples in John 20:23 that, with the Spirit inside them, they will even have the authority to forgive or prevent the forgiveness of sins.
These are truths with regard to which Protestants have especially seen great danger. We must assume, for example, that it is only when a church is in sync with the Holy Spirit that its pronouncement of forgiveness or lack thereof is in fact valid. It is only when we ask in sync with the Holy Spirit that things are truly bound or loosed.
Nevertheless, these Scriptures seem to legitimate what in fact must be the case today. Since the apostles are no longer with us and the Scriptures will often not address directly the situations of our days, collections of Christians must "bind and loose" God's authority on earth in various ways. It is legitimate for collections of Christians, such as denominations, to follow the will of God as best they can on earth, humbly seeking and submitting to the voice of the Holy Spirit, leading them into all truth.
6. A final note is that the Spirit is the great equalizer in the Church. Since both men and women receive the Holy Spirit in exactly the same way, both men and women prophesy (Acts 2:17). Because both slaves and free, both Jew and Gentile receive the Spirit equally, then there is no differentiation of status in the kingdom of God (Gal. 3:28).
There is no gift of the Spirit that is particular to men or the free or the Jew. The Spirit leads men into truth and the Spirit leads women into truth. Men can lead in the Church and women can lead in the Church. The slave can lead the master into truth and the wife can teach the husband, if the Spirit is within them. Individual circumstances in history may complicate the application of these principles, but this is the way it is ideally in the age of the Holy Spirit.
The Holy Spirit sanctifies the Church. He purifies it and creates it by setting it apart as God's. He empowers it for unity. He empowers it for witness and gives individual manifestations and gifts for the mission and the edification of other believers. He leads it into truth.
 It is no surprise that the historic practice of infant baptism has fallen on hard times among individualistic American Christians, for with such a paradigm, how could my baptism take place at a time when I am not aware of it or when I cannot make my profession of faith?
 You can see this obvious dynamic in the Greek words. The verb "to sanctify" is hagiazo. The adjective, "holy," is hagios (the plural hagioi or "holy ones" is often translated as "saints). And the noun, "holiness," is hagiosyne. Obviously these words are all related historically, and their meanings remained intertwined at the time of the New Testament.
 Yes, where the Spirit of the Lord is, there is freedom (2 Cor. 3:17), but this is not a freedom for each individual to do what he or she wants (cf. 1 Cor. 10:23). Paul is dealing with the Jewish Law in this comment, which was not binding on Gentile believers.
 As we will see in a later article, the inspiration or "God-breathing" of meaning into the words of the Bible has never been static but is an ongoing, dynamic speaking.