This is now the fourth and final post in a unit on the Holy Spirit in my ongoing series, theology in bullet points. The first unit had to do with God and Creation, and the second was on Christology and Atonement.
The Spirit sanctifies the believer.
1. In terms of priority, the body of Christ is primary, and the individual believer is secondary. Yet every individual is valued equally, created in the image of God, male and female, people of every tribe and nation, people of every status. All are loved whether sinner or saint.
God is love, so he loves every individual. But there are many individuals in the Church. So it seems obvious that there is more love dispensed to the Church as a whole than to any one individual in the Church. The health of the whole Church takes priority over the liberty of the individual Christian (e.g., Rom. 14; 1 Cor. 10).
Accordingly, the way in which the Spirit engages the individual is a microcosm of the way he engages the Church as a whole. The Spirit sanctifies the Church and makes it God's own. So the Spirit sanctifies the individual believer. The Spirit purifies the Church and makes it righteous, and the Spirit purifies the believer and makes us righteous. The Spirit empowers the Church for mission and service. The Spirit empowers the individual for mission and service. The Spirit leads the Church into truth. The Spirit leads individuals into truth.
2. If Christ is the basis of atonement, all the grace relating to salvation is dispensed through the Holy Spirit. It is the Holy Spirit that dispenses prevenient grace, the grace that comes to us before we are able to go looking for God. It is the grace that enables us to move toward God. It is the grace that empowers us to be able to repent and exercise faith.
It is the Holy Spirit that dispenses the grace that justifies us and acquits us of all our sin. The Holy Spirit is God's "seal" of ownership (2 Cor. 1:22), such that if someone does not have the Spirit, that person does not truly belong to Christ (Rom. 8:9). The Holy Spirit is an "earnest" of our eternal inheritance (2 Cor. 5:5; Eph. 1:13-14), which is both a guarantee of that coming promise and a down payment of what is to come, a "foretaste of glory divine."
The Holy Spirit is thus the central factor in the incorporation of a person into the body of Christ. You can be baptized and not have passed from death to life (Acts 8:16). You can have passed from death to life and not been baptized (Acts 10:44-48). You can have undergone significant change and movement toward a godly and righteous life. You can have prayed the sinner's prayer and agreed to all the creeds of Christendom with your head.
But unless a person has the Holy Spirit, he or she is not yet in Christ.  It is the Holy Spirit that gives witness to our spirits that we are children of God (Rom. 8:16). The Holy Spirit thus brings us the assurance that we are children of God. It is the act of the Holy Spirit whereby we become "in Christ" and when we speak of Christ in us, we are speaking of the Spirit of Christ, Christ's presence in us somehow mysteriously mediated by the Holy Spirit.
3. It is somewhat popular at the moment to speak of conversion as a long gradual process rather than an instantaneous one.  There is of course a good deal of truth in this claim. It usually does take a good deal of time for a person to change.
It's also a slightly different question from whether you will escape the judgment. Most believe that unbaptized children will escape the final judgment, and yet they have neither been baptized nor have they received the Holy Spirit. If so, then one can technically be "saved" in that sense without baptism, faith, or having even received the most crucial element of all--the Holy Spirit.
But the Holy Spirit comes in an instant, and in that sense, you become part of the people of God in a moment. There may be a long process leading up to that point, and there is almost always a long process thereafter. But this is a different issue than being baptized into Christ by receiving the Holy Spirit, which must thereby always happen definitively in a moment.
The disciples cannot be used as an example of gradual incorporation into the body of Christ, even if they changed gradually. The Holy Spirit simply was not given in the manner of the new covenant until the Day of Pentecost. In that sense, none of the disciples were "in Christ" until the Day of Pentecost, when they were baptized into Christ in an instant. 
4. How does one know that this baptism, this receiving of the Holy Spirit has taken place? There can and often have been noticeable signs. The book of Acts testifies to the sudden ability to speak in other languages, a sudden boldness to proclaim Christ's resurrection, the sudden ability to perform miracles and healing. In the American revivals of the eighteenth, nineteenth, and twentieth centuries, people often felt an overflow of emotions and might start shouting or even running the aisles of a church.
But did everyone in the early church experience these sorts of dramatic manifestations or emotions? Not likely. We can imagine that the most typical manifestation of the Holy Spirit is a sense of peace and assurance, a sense that, in fact, you are received by God and at peace with him.
No doubt there will be some who do not feel different. Some, perhaps because of their past, may not feel anything at all. But are you truly committing to God with your whole will to the extent you know how? Are you making a choice of faith for God? Are you willing to make that faith public, including a public confession of faith in baptism?
Then you should trust that your sins are forgiven and that the Holy Spirit has taken control over your life. Sometimes God uses others to give us an assurance in such cases. Seek out someone you trust. God often empowers others in the body of Christ, especially those he has called to minister, to proclaim to us that our sins are indeed forgiven (cf. John 20:23).
3. The Holy Spirit thus sanctifies us and sets us apart as belonging to God. He purifies us of our guilt of sins past and he overcomes the power of Sin present and future. The Holy Spirit is behind initial sanctification, the act of cleansing us of our past sins and setting us apart as God's children. The Holy Spirit is behind progressive sanctification, the increase of righteousness and godliness in our lives.
When we get to the point of complete surrender of all our lives in every way we know how, the Holy Spirit can sanctify us entirely, making it easy to do the good we want to do. But we will always have room for growth until the day when we are glorified, when our mortal, corruptible bodies, our flesh subject to Sin and temptation, is transformed into resurrected bodies that are made like Christ's glorious resurrection body.
The Holy Spirit thus empowers us for obedience. The Holy Spirit imparts righteousness and godliness to the believer so that we are not only legally in right standing before God, but the Spirit actually makes us good. We are not, as Luther taught, doomed always to be both sinner and saint, but the Spirit empowers us not only to do the good but even to want the good. 
3. The Holy Spirit not only empowers us for purity. He also empowers us for ministry. We have already mentioned the manifestations of the Holy Spirit in Acts. The Church is praying in an upper room in Jerusalem when the Holy Spirit comes on the Day of Pentecost. The Church is born. The Spirit brings everyone there into Christ.
Immediately we see a change. They are witnessing with boldness to the crowds, even in languages they have never learned. The next day, Peter and John heal a lame man. Later in Acts they and others will cast out demons.
The mission of the Church is the mission of God. The mission of God is the redemption of everything in the creation. The Spirit empowers the Church--both on an individual and corporate level.
The Holy Spirit sanctifies the believer. He purifies us. He incorporates us each individually into the body of Christ. He empowers us.
Next Sunday: E1. The Church is the body of Christ.
 We are not talking about tongues here, for not all who receive the Holy Spirit in Acts speak in tongues and the rest of the New Testament is practically silent on the topic, except for a couple chapters in 1 Corinthians.
 E.g., Richard Peace, Conversion in the New Testament: Paul and the Twelve (Grand Rapids: Eerdmans, 1999).
 In this sense, Peace's book is inadvertently trying to address two quite different questions at once, one a question of change and the other a question of incorporation. Given this blurring of questions, it is no surprise that his book barely mentions the most important element in conversion of all--the Holy Spirit.
 Simul iustus et peccator, semper repentans -- "At the same time, righteous and a sinner, as long as we are always repenting"