Why is the Holy Spirit important?

Most people first meet the Holy Spirit in Acts chapter 2, with the wind and the fire and the crowd in Jerusalem. It is easy to come away thinking He arrived late — that the Father worked in the Old Testament, the Son worked in the Gospels, and the Spirit turned up afterwards to look after the church.

But He appears as early as the second verse of the Bible.

Genesis 1:2 (NKJV)

The earth was without form, and void; and darkness was on the face of the deep. And the Spirit of God was hovering over the face of the waters.

Before there was light, before there was land, the Spirit of God was there over the water. There has never been a moment when God worked without Him. The Father made all things through the Son, and He did it by His Spirit.

He worked all through the Old Testament, and He worked in ordinary people. Bezalel was a craftsman. God chose him to build the tabernacle and said of him, “I have filled him with the Spirit of God, in wisdom, in understanding, in knowledge, and in all manner of workmanship” (Exodus 31:3). Gideon was a frightened farmer. When Israel needed rescuing, “the Spirit of the LORD came upon Gideon” (Judges 6:34), and he led an army. David was a shepherd boy. On the day Samuel anointed him king, “the Spirit of the LORD came upon David from that day forward” (1 Samuel 16:13). And the prophets spoke for God only because “holy men of God spoke as they were moved by the Holy Spirit” (2 Peter 1:21).

But notice the pattern in all of it. The Spirit came upon particular people, for particular work, and He could leave again. Scripture says plainly of Saul that “the Spirit of the LORD departed from Saul” (1 Samuel 16:14), and David, who had watched it happen, prayed, “Do not take Your Holy Spirit from me” (Psalm 51:11). In the Old Testament the Spirit was given to some, not to all.

Then God promised something better.

Ezekiel 36:26–27 (NKJV)

I will give you a new heart and put a new spirit within you; I will take the heart of stone out of your flesh and give you a heart of flesh. I will put My Spirit within you and cause you to walk in My statutes, and you will keep My judgments and do them.

Read what God takes responsibility for. He removes the stone heart. He supplies the new one. He puts His Spirit inside. He causes the obedience. Nobody is asked to soften his own heart first and be given the Spirit as a reward. A stone heart cannot soften itself, which is why a promise like this was needed at all.

Joel added the reach of it.

Joel 2:28–29 (NKJV)

And it shall come to pass afterward that I will pour out My Spirit on all flesh; your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions. And also on My menservants and on My maidservants I will pour out My Spirit in those days.

“All flesh” does not mean every person on earth. It means every kind of person, and Joel's own list shows it: sons and daughters, old and young, servants as well as masters. Under the old covenant the Spirit came on a few. Under the new He would be poured out across the whole people of God, with no group left outside.

Before that day came, the Spirit rested on Christ Himself. Jesus stood up in the synagogue at Nazareth, opened the scroll of Isaiah, and read these words over His own ministry:

Luke 4:18 (NKJV)

The Spirit of the LORD is upon Me, because He has anointed Me to preach the gospel to the poor; He has sent Me to heal the brokenhearted, to proclaim liberty to the captives and recovery of sight to the blind, to set at liberty those who are oppressed;

The Son of God did His earthly work in the power of the Holy Spirit. No Christian should expect to serve God on his own strength.

Then came the day Joel had spoken about.

Acts 2:1–4 (NKJV)

When the Day of Pentecost had fully come, they were all with one accord in one place. And suddenly there came a sound from heaven, as of a rushing mighty wind, and it filled the whole house where they were sitting. Then there appeared to them divided tongues, as of fire, and one sat upon each of them. And they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit gave them utterance.

The detail to catch is the smallest one. One sat upon each of them. Not one flame over the leader, but one for every person in the room. The promise landed exactly as Joel said it would.

The men who had run away when Jesus was arrested walked out into the city and preached to the crowd that had killed Him. Peter, who weeks earlier could not admit to a servant girl that he knew Jesus, told them to their faces that they had crucified their own Messiah — and then told them that they could be forgiven for it. Three thousand believed that day.

So here is why the Holy Spirit matters. God does not save people from a distance. He comes and lives in them. At every point where His work has touched this world — the making of it, the writing of Scripture, the ministry of Jesus, the birth of the church — the Spirit is the One who brought that work home.

And what was given at Jerusalem was not on loan to a gifted few. Paul writes that “if anyone does not have the Spirit of Christ, he is not His” (Romans 8:9). Every Christian has Him. Nor does He come and go as He did in Saul's day, because Paul says believers were “sealed” by Him “for the day of redemption” (Ephesians 4:30). The seal holds to the end. David prayed that God would not take His Holy Spirit from him. No Christian has to pray that prayer.