Joel 2:28-32, quoted by Peter in Acts 2, is the central prophecy of God pouring out His Spirit on all flesh. Under the Old Testament, the Spirit came upon selected individuals such as Joseph, Joshua, the judges, Saul, and David for specific tasks, and sometimes departed, as with Saul. Moses' longing in Numbers 11:29 that all the Lord's people were prophets is the root of Joel's promise. At Pentecost in AD 31 the fulfillment began as a type, and the Spirit was no longer reserved for a few but offered to all believers regardless of age, sex, or station, making the church a royal priesthood. Joel's prophecy will be fulfilled comprehensively only after the Day of the Lord and Christ's return, when the Spirit will be poured out globally through the Millennium on Israel and the Gentiles. The evidence of being filled with the Spirit is a witness to Jesus Christ, as the nine New Testament cases of filling show, and above all repentance, humility, and Christ-like service rather than showy gifts. The Spirit equips each member with gifts for service, and ministers are to equip the saints as shepherds, not lords. Believers are called to live Spirit-led lives, proclaim the truth, and be transformed into Christ's image (II Corinthians 3:17-18).

The Holy Spirit is the power and mind of God, not a separate personage or part of a trinity. Because it emanates from God, it can be poured out (Titus 3:5-6), breathed (John 20:22), and used to fill (Acts 2:4) and anoint (Acts 10:38). God gives it to those who ask, but only to those who have shown by attitude and behavior that they have repented, been baptized, and obeyed His commandments. No one who continues to live apart from God's law has received it. Since Adam rejected God's offer in Eden, God has not offered His Spirit to humanity as a whole. Since Christ established the church, He has given it only to those He calls to be firstfruits (John 7:39). In the World Tomorrow, when Christ returns, God will give everyone the opportunity to receive it, as the prophecies of Joel 2:28-29 and Ezekiel 39:29 foretell. The Spirit is a gift that no one is born with or can earn. It opens the mind to God's truth, imparts wisdom, comforts, and aids prayer, and it delivers from death by endowing eternal life. Its presence is shown by the fruit of the Spirit, which shapes the character of Christ in the believer.

In 31 AD, after His crucifixion, Jesus appeared to His disciples and breathed on them, declaring, Receive you the Holy Spirit. He instructed them that this was a gift from their Father, urging them to wait in Jerusalem to receive it. With the receiving of the Holy Spirit comes the responsibility of living in a manner that reflects this gift, acting as a light to the world through the correct way of living. This responsibility is vital, as it influences Jesus Christ's decision to save the world for the sake of the elect. When Pentecost arrived, the disciples were assembled in unity in one place. Suddenly, a sound like a mighty wind filled the house, though no air moved, creating an awe-inspiring miracle. Above them, fire appeared in the form of cloven, tongue-shaped flames, resting on each of them without heat. They were filled with the Holy Spirit, and the power of God manifested as they began to speak in unfamiliar languages, marveling at this gift. A multitude gathered, and through the Holy Spirit, every man understood the message in his own language and dialect, despite the Galileans' reputation for crude speech. The message conveyed was of the wonderful works of God, marking the introduction of His Holy Spirit to the world in a spectacular fashion. The Holy Spirit is the power of God in action, inspiring and accomplishing feats through individuals. It fills with superhuman strength and great courage, enabling extraordinary acts as seen in the feats of David's mighty men. This Spirit continues to work in behalf of God's people, intervening in times of need. It serves to teach personally, shaping the will of the individual through righteous knowledge, reminding them of Jesus Christ's obedience, faith, and character to imitate His way of living. The Holy Spirit bears witness to the truth, amplifying it amidst a world of persecution and hatred, urging obedience to God's laws through love, kindness, and service. This gift of the Holy Spirit, given as a down payment of inheritance, seals God's people as authentic and approved, marking them as members of His family. It guides into divine truth, freeing from the lies and superstitions of the world, and declares His will individually. Though powerful, the Holy Spirit can be quenched by the attractions of the world if valued more than obedience to God. It provides the power to overcome, developing godly character essential for becoming sons of God, resisting the wiles of Satan through faith and righteous living. God's intent is for this Spirit to remain with His people, influencing their thinking in obedience and filling them with hope for the final transformation into members of His family.

The Holy Spirit is the power of God, not a personality within the God family. Scripture describes it with language that cannot fit a person: it falls on people, is poured out like a drink, and fills a whole house like a rushing mighty wind. In Acts 10:44-45 the Holy Spirit fell on Cornelius and his household and was poured out on the Gentiles, and in Acts 2 it came as a rushing mighty wind that filled the house. Acts 2:17-18 has God say, "I will pour out of My Spirit on all flesh," which means pouring out His power. A personality cannot be poured out, fall upon people, or fill a house, so these descriptions show something inanimate, an "it." Luke 1 calls the Holy Spirit "the power of the Highest," and Acts 1:8 says power comes when the Holy Spirit comes. The Father and Son send this power forth from their minds to call, convict, lead to baptism, and begin creating us into the God kind. It is the means by which God, who is located in one place, acts anywhere in His creation. Psalm 139:7 calls it His Spirit, belonging to the Father. Water and oil are figures for it, and the apostles' greetings mention only the Father and the Son.

The outpouring of the Holy Spirit is the Promise of the Father, and it could not come until Christ had ascended. On the 40th day Jesus commanded the apostles to wait in Jerusalem, because He had to go to the Father before He could send the Comforter. The breath He gave them after His resurrection was only a foretaste. The full outpouring came on the 50th day, Pentecost, fulfilling prophecies such as Joel 2:28-29, Ezekiel 36:26-27, and Isaiah 44:3. The Spirit is the gift Christ received from the Father in His victory and then gave to men, as Psalm 68:18 foretold of a conqueror who leads captivity captive and gives gifts so that God may dwell with His people. Peter explains in Acts 2 that the events of Pentecost are the direct result of Jesus being exalted to the Father's right hand: having received the promise of the Spirit, He poured out what the crowd saw and heard. This manifestation is evidence of who Jesus is and of the position He holds, as both Lord and Christ. The same Spirit that animated Jesus empowers the apostles to be witnesses. It imparts knowledge, understanding, and wisdom, and impels toward holiness, power, love, and a sound mind. The truest witness is lives conformed to Christ's image, men living as God lives. The apostles told the council that the Spirit is given to those who obey God, so the rebellious leaders had missed the gift.

The outpouring of the Holy Spirit on Pentecost in 31 AD founded the Church of God and was introduced to the world with signs, chiefly speaking in tongues. In Acts 2 the disciples were filled with the Spirit and spoke in real human languages new to them, while the Jewish and proselyte hearers from many nations each heard in the tongue of their birth. This was a double miracle of speaking and hearing, and it is the pure, unperverted example of the gift. Its purpose was to communicate the gospel to unbelievers and to confirm the message as a sign, fulfilling Isaiah 28:11, and about three thousand were added that day. The Spirit was poured out again in Acts 10 on the Gentiles and in Acts 19 on the disciples at Ephesus, and tongues each time assured the hearers that the message was true. Being baptized into the body of Christ by the Spirit does not require tongues, since not all in Corinth spoke in them. To be filled with the Spirit is to live a Christ-like life and bear its fruit of love, joy, and peace, and neither Jesus nor John the Baptist spoke in tongues. Because God now gives the completed Bible to confirm the message, tongues have ceased, and modern tongues-speaking is not from God.