The Bible’s Answer
The Holy Spirit is the Third Person of the Holy Trinity, and he plays a pivotal role in the lives of every person in the world. The work of the Holy Spirit primarily revolves around converting people to the Christian faith and bearing witness to Jesus Christ. He does all this through the Word of God (as it is written or spoken) and the sacraments (baptism and Holy Communion). As a personal being, the Holy Spirit also functions as the primary spiritual teacher of Christians throughout their lives.
The Holy Spirit Makes Disciples of Christ
While Peter was still saying these things, the Holy Spirit fell on all who heard the word. And the believers from among the circumcised who had come with Peter were amazed, because the gift of the Holy Spirit was poured out even on the Gentiles. For they were hearing them speaking in tongues and extolling God. (Acts 10:44–46, ESVUK)
Converting to Christianity is a supernatural experience. As we can see from this Bible passage, people become Christians the moment the Holy Spirit indwells them (see also Ephesians 1:13–14). He gives us faith in Jesus Christ (1 Corinthians 12:3), which is a gift of God’s grace alone (Ephesians 2:8–9). When the Holy Spirit enters people, he also changes their lives. In fact, the Holy Spirit gives Christians a spiritual rebirth in baptism (John 3:3–5)—killing the power of the old sinful nature (Romans 6:5–7) and making them a new creation (2 Corinthians 5:17), through whom God does his good works (Philippians 2:12–13).
In this instance, the Spirit-filled Gentiles spoke other languages and praised God as a result. These days, the Holy Spirit does not usually give Christians the gift of tongues (except for when he, in his wisdom, deems it necessary), but he does give each Christian a spiritual gift that they can use to serve God and one another, such as knowledge (1 Corinthians 12:7–11) and generosity (Romans 12:6–8). One thing the Holy Spirit does for every Christian is that he fills them with the love of God (Romans 5:5), which gives them grateful hearts towards God, ready and willing to serve him.
The Holy Spirit Works through the Word and Sacraments
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. (Acts 2:38–39)
As we saw in the passage before, the Holy Spirit came upon the disciples when they heard the Word of God from Peter (Acts 10:44–46). Here, we see that the Holy Spirit also comes upon us when we are baptised. This logically follows since baptism is water combined with the Word of God (Ephesians 5:25–26). Furthermore, because the Lord’s Supper is bread and wine consecrated by Christ’s words (Matthew 26:26–28), we see from this that the Holy Spirit also works through Holy Communion.
This tells us an important biblical truth: the Holy Spirit operates and does his works exclusively through the Word and sacraments. Therefore, we can be assured that, even if we are not the most intelligent or charismatic of Christians, our words are powerful if we faithfully confess God’s Word. Therefore, Paul can say that the gospel (that is, the good news of salvation in Jesus) is “the power of God for salvation to everyone who believes” (Romans 1:16). Where the Word of God is proclaimed, there the Holy Spirit will be, powerfully at work to create and strengthen biblical faith, both in us and in those to whom we proclaim the Word (1 Thessalonians 1:5).
The Holy Spirit Saves Us
And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God. (1 Corinthians 6:11)
God justifies us by faith alone in Jesus—a God-given gift—not by our works (Romans 3:28). When God justifies us, he declares us righteous for Christ’s sake, allowing us to enter Heaven after we die and avoid the penalty of our sins: eternal punishment in Hell (Romans 4:5; 8:1). By the Holy Spirit, we are justified in Jesus’ name because of his perfect life (Romans 5:19), his atoning death for all our sins on the cross, and his resurrection from the dead (Romans 4:24–25). This means that the Holy Spirit delivers to us the benefits of Jesus’ saving works that he won for us: the forgiveness of sins, eternal life, and salvation (Titus 3:4–7). He does this through the Word and sacraments, as we have noted above.
The Holy Spirit Bears Witness about Jesus
But when the Helper comes, whom I will send to you from the Father, the Spirit of truth, who proceeds from the Father, he will bear witness about me. (John 15:26)
A good way of knowing whether or not someone is preaching in (or by the power of) the Holy Spirit is if their teaching focuses on the biblical Jesus, just as the Holy Spirit does. If Jesus and his saving works are not at the centre or forefront of it—if they prioritise “practical application” for our lives or “holy living” over Jesus and his works—then such teaching actually hinders the work of the Holy Spirit. The Holy Spirit, though fully equal with Jesus and the Father (Acts 5:3–4), humbly serves to glorify Jesus Christ, not himself (John 16:14). He not only bears witness about Jesus to the church, but he bears witness to the whole world (John 16:8–11).
The Holy Spirit Is Our Teacher
When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come. (John 16:13)
On a more personal level, the Holy Spirit, who lives within every Christian (1 Corinthians 3:16–17), acts as our Paraklete (that is, our Helper, Comforter, Counsellor, and so on). He is our spiritual legal advocate, who defends us from Satan and his followers, encourages and comforts us in our troubles, and guides us in our faith (John 14:26). The Bible promises us that when we have to give an account of our Christian faith in the face of persecution, the Holy Spirit will teach us what we ought to say (Luke 12:11–12). Not only that, but because he seals us for the day of redemption (Ephesians 4:30), the Holy Spirit gives us the assurance of our salvation in Christ.
The Holy Spirit Sanctifies Us
Peter, an apostle of Jesus Christ, To those who are elect exiles of the dispersion in Pontus, Galatia, Cappadocia, Asia, and Bithynia, according to the foreknowledge of God the Father, in the sanctification of the Spirit, for obedience to Jesus Christ and for sprinkling with his blood: May grace and peace be multiplied to you. (1 Peter 1:1–2)
In addition to teaching us, the Holy Spirit also sanctifies us. This means that he makes us holy (that is, sets us apart from evil) so that we produce the fruits of the Spirit throughout our lives, such as love, patience, and self-control (Galatians 5:22–23). This does not mean that we become sinless (1 John 1:8, 10), nor does it mean that we immediately become better people. The Bible teaches that sanctification is a life-long process (2 Corinthians 3:18). Christians will still struggle against sin and succumb to it since they are not perfect (just as no one else is), but God promises us in his Word that he will forgive us if we confess our sins to him (1 John 1:9). However, because we have the Holy Spirit and are led by him (Romans 8:14), we will naturally walk by his righteous ways to the best of our ability, rather than gratify the sinful desires of our flesh (Galatians 5:16; see also 1 John 3:9–10).
The Holy Spirit converts people to Christianity and strengthens every Christian’s God-given faith through God’s Word and sacraments. The Holy Spirit has a personal relationship with Christians throughout their lives, dwelling within them as his temple, teaching and guiding them, and comforting and encouraging them as their Paraklete (their Counsellor or Helper). Because of the Holy Spirit, Christians can have assurance of their salvation, and they can live the way God wants them to live, rather than be controlled by their sinful nature. If you would like to receive the Holy Spirit and his wonderful works, then put your faith in Jesus Christ as your God and Saviour, and you will be saved (Titus 2:13–14; Hebrews 9:27–28).