The New Testament church was established and the door to it was opened in the Book of the Acts of the Apostles. Since the church was founded on the Day of Pentecost with the coming of the Holy Spirit, today those who receive the Holy Spirit with the evidence of speaking in tongues as did the disciples in Acts 2 are called Pentecostal.
The Gospels describe the ministry of Jesus and His wonderful work in laying the foundation for the New Testament church, the spiritual kingdom in this age. The Gospels record Christ's commands to repent and to be baptized and His promise to pour out the Holy Spirit, but Christian water baptism and the baptism of the Holy Spirit did not take place until after Jesus was crucified, rose from the dead, and ascended to heaven. In the Gospels, Jesus spoke of the founding of His church in the future tense: "I will build my church" (Matthew 16:18). During that time, "the Holy Ghost was not yet given; because that Jesus was not yet glorified" (John 7:39). After Christ's ascension, the church was established when His followers were baptized with the Holy Spirit and spoke in tongues as the Spirit gave utterance (Acts 1:4-9; 2:1-4).
The Book of Acts
Matthew, John, and the other apostles were all present on the Day of Pentecost when the Holy Spirit was first given. They were all witnesses to Peter's marvellous message and supported him as he opened the door of salvation (Acts 2:14). When the audience cried out under conviction of sins, "Men and brethren, what shall we do?" Peter replied, "Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost" (Acts 2:38).
Peter had the authority to proclaim the way of entrance into the church, for Christ had given him the "keys of the kingdom of heaven" (Matthew 16:19). No one disputed his answer or his authority to give it. Repentance was accepted as essential to entering the kingdom. Moreover, the formula Peter gave for water baptism was not controversial, for the apostles understood the identity of Jesus as the one God manifested in the flesh (Colossians 2:9; I Timothy 3:16). They realized that He was the embodiment of the eternal Spirit of God, whom He as a man called His Father. Therefore, there was no argument when Peter commanded water baptism to be administered in the name of Jesus Christ. Finally, the promise of the Holy Ghost was not new since Jesus said that all who believe on Him would receive the Spirit (John 7:38-39).
Peter used the same keys to open the door of salvation to the Gentiles (Acts 10), and they received the same experience that the disciples did on the Day of Pentecost (Acts 2). Moreover, the same keys were used in proclaiming the message of salvation to the Samaritans; they were baptized in the name of the Lord Jesus and filled with the Holy Spirit (Acts 8). A few years later, the Apostle Paul rebaptized the disciples of John the Baptist in the wonderful name of Jesus, and they too received the Spirit and spoke in tongues (Acts 19). Thus, the Book of Acts consistently presents the same keys - the same plan of salvation.
The Epistles contain instructions to various churches, such as the churches at Corinth and Ephesus, and to individuals, such as Timothy and Titus. They were written to instruct people who had already entered the door of salvation. The Book of Acts records the founding of many of the churches to which these letters were written, and the Epistles frequently refer to the readers' prior repentance, baptism in Jesus' name, and baptism of the Holy Spirit. (See, for example, Romans 6:1-4; I Corinthians 6:11; 12:13; Galatians 3:2, 27; Titus 3:5.)
Opponents of the Pentecostal truth err by going first to the Epistles and virtually ignoring the Book of Acts, where the plan and experience of salvation is recorded. Many passages in the Epistles explain how salvation is made available to humanity, namely, by grace through faith based on the atoning death, burial, and resurrection of Jesus Christ. (See Romans 3:21-26; Ephesians 2:8-9.) Moreover, many passages describe qualities that characterize the life of true Christians, such as "We know that we have passed from death unto life, because we love the brethren" and "Whosoever believeth that Jesus is the Christ is born of God" (I John 3:14; 5:1). But none of these statements cancel the command of Acts 2:38 and the actual experience of the new birth as promised in the Gospels, received in Acts, and referred to in the Epistles.
The gift of tongues mentioned in Paul's first epistle to the Corinthian church is one of nine spiritual gifts that a saint, a person who is filled with the Spirit (not an unbeliever), may or may not receive. No one can exercise the gift of tongues or any of the nine gifts who has not previously received the Holy Spirit with the initial sign of speaking in tongues (Acts 2:4).
The Gospels point to the way of salvation and the Epistles confirm it, but the door of salvation is opened in the Book of Acts. The born-again experience, which consists of repentance, water baptism by immersion in the name of Jesus, and the baptism of the Holy Spirit as evidenced by the heavenly witness of speaking with other tongues, has never changed since the Day of Pentecost (Acts 2:4, 38). No one has the authority or power to change it, not even an angel from heaven (Galatians 1:8). The gates of hell shall not prevail against it (Matthew 16:18). This experience is imperative if we are to be ready for the soon coming of the Lord.