The indwelling of the Holy Spirit—What is it?

TL;DR:

The indwelling of the Holy Spirit is God taking up permanent residence in the heart of those who have placed their faith in Jesus Christ as Savior. With the indwelling of the Holy Spirit, believers are never alone and never without power.

what does the bible say?

The indwelling of the Holy Spirit means that God Himself permanently lives in every believer through faith in Jesus Christ. In the Old Testament, the Spirit came upon people for specific tasks but could also depart, while at Pentecost, He began to permanently dwell within all who belong to Christ. This indwelling brings new life, confirms our identity as God’s children, imparts spiritual gifts, teaches us God’s Word, intercedes in prayer, and produces His fruit in our lives. The Spirit also seals us for eternity, assuring us of our salvation and future with God. Because our bodies are His temple, we live with the constant presence, power, and guidance of God Himself within us.

from the old testament

In the Old Testament, the Spirit would come intermittently upon the saints, empowering them for service, but not necessarily remaining with them. The Spirit "rushed upon" Lehi (Judges 15:14) and "clothed" Amasai (1 Chronicles 12:18).
The Spirit was with David and able to be removed from him (Psalm 51:11), and the Spirit "fell upon" Ezekiel and spoke to him (Ezekiel 11:5).
The Spirit, who had once been with King Saul, "departed from" him, removing His influence and guidance from the king (1 Samuel 16:14). It wasn't until Pentecost that the Spirit began to indwell those who belong to God through Christ.

from the new testament

Jesus predicted the coming of the Spirit, who would live within His people (John 14:16–17), as well as the new role the Spirit of Truth would play in their lives by guiding them into all truth (John 16:13).
Prior to the resurrection and Pentecost, the Spirit was with the disciples and influenced them, but He did not yet indwell them, as Jesus explained to them: "he dwells with you and will be in you" (John 14:17, italics added). John 7:39 explains further: "Now this he said about the Spirit, whom those who believed in him were to receive, for as yet the Spirit had not been given, because Jesus was not yet glorified."
The apostle Paul reiterated the same truth about the Spirit's indwelling: "Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God? You are not your own, for you were bought with a price. So glorify God in your body" (1 Corinthians 6:19–20). Because believers have been purchased for God by the blood of Christ, shed on the cross for our sins, our bodies become a living temple where the Spirit of God resides.
The purpose of the indwelling of the Holy Spirit is many-faceted. First and foremost, the Spirit creates new life in believers (Titus 3:5), producing the same new birth Jesus spoke of in John 3:1–8. The Spirit confirms to us that this new birth is real and that we truly belong to God (Romans 8:15–17). He also imparts to believers spiritual gifts to be used to build up the body of Christ and glorify God (1 Corinthians 12:4–11). Further, as the author of Scripture through the writers He inspired (2 Timothy 3:16), the indwelling Spirit helps believers understand what He has written and how to apply it to daily life (1 Corinthians 2:12).
Other functions of the indwelling Spirit include interceding for believers in prayer (Romans 8:26), leading us in the ways of righteous living (Romans 8:14), producing His fruit in our lives (Galatians 5:22–23), and installing believers into the universal church of Christ, also called the baptism of the Spirit (1 Corinthians 12:13).
One of the indwelling Spirit's most encouraging functions is to seal believers for eternity by placing His own mark upon us. Doing so assures our arrival in the Lord's presence when we die (Ephesians 1:13–14; 4:30).

implications for today

The image of the believer's body being a temple is reminiscent of the Old Testament tabernacle or temple, in which the Spirit of God lived. There, God's presence would appear in a cloud and meet the high priest, who came once a year into the Holy of Holies. On the Day of Atonement, the high priest brought the blood of a slain animal and sprinkled it on the mercy seat of the Ark of the Covenant. On this special day, God granted forgiveness to the priest and His people (Leviticus 16).

The Jewish temple in Jerusalem no longer exists. Now, the believer in Christ has become the inner sanctum of God the Holy Spirit, as the believer has been sanctified and forgiven by the blood of Jesus Christ (Ephesians 1:7). In fact, Scripture also says that the believer is the dwelling place of all three Persons of the Trinity. Along with the Spirit, Jesus Christ is in us (Colossians 1:27), as is God the Father (1 John 4:15).

The Holy Spirit's presence within us is the guarantee that we have been purchased by Christ and redeemed from our sins. We can never lose our position as a prized possession. Until we die, the Spirit remains within us, renewing and sanctifying us, comforting us in trials, and sustaining us in afflictions. With the indwelling Holy Spirit, we are never alone, never lost, and never without His power.

understand

The Holy Spirit permanently indwells every believer.
The Holy Spirit transforms, empowers, and guides believers.
The Holy Spirit seals and secures our salvation forever.

reflect

How does knowing that the Holy Spirit permanently lives within you change the way you see your life?
In what areas of your life do you need to rely more on the Spirit’s power, rather than your own strength?
How does the truth that your body is the Spirit’s temple shape the way you make choices in daily life?

engage

How can we better encourage one another to depend on the Spirit’s guidance instead of our own wisdom?
What can we learn from the contrast between the Spirit’s temporary presence in the Old Testament and His permanent indwelling in the New Testament?
How can we recognize and celebrate the Spirit’s work of transformation and assurance in each other’s lives?