On speaking in tongues, Acts 10:44-48 states the Holy Spirit fell upon the Gentiles upon hearing the Word of God preached by Peter. That the Gentiles were speaking in tongues was the immediate evidence to the Jews that God had given the Gentiles the same gift of the Spirit as He had the Jews. It should also be noted that the Gentiles received the Spirit before they had been baptized by water, but that is another discussion. Let’s review the passage:
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. Then Peter declared, “Can anyone withhold water for baptizing these people, who have received the Holy Spirit just as we have?” And he commanded them to be baptized in the name of Jesus Christ. Then they asked him to remain for some days. (Acts 10:44-48 ESV)
The purpose of tongues here was to demonstrate God’s salvation purposes through all people from all nations. The event follows Peter’s vision that God had made the Gentiles clean, and there was to be no division between Jew and Gentile in Christ. It also demonstrates that tongues speaking (which is biblically defined as speaking in unlearned, known earthly languages), served a unique purpose in the early church and is no longer a gift distributed by the Spirit. A significant evidence of this is that believers today, upon conversion, do not speak in biblical tongues.
Some charismatic denominations teach that speaking in tongues is subsequent to conversion. They teach the baptism of the Holy Spirit is distinct from the new birth, and this second baptism is necessary to live a complete and holy Christian life. It is expected that every believer should seek this baptism. The implication is as follows: no speaking in tongues means one has not been baptized in the Holy Spirit. If one has not been baptized in the Holy Spirit, then one has not received the Holy Spirit. If one has not received the Holy Spirit, then one is not saved, because all who have received the Spirit will speak in tongues giving evidence of Spirit baptism subsequent to conversion.
What we indeed see in Acts 10:44-48 is these Gentile believers received the Holy Spirit then spoke in tongues, followed by water baptism. This gift of speaking in tongues was not only subsequent to conversion, but immediately followed conversion. While God poured out His Spirit to both believing Jews and Gentiles in the New Testament to build and bring unity in His church, and the evidence He was doing so was through the external evidence of speaking in tongues, no such evidence is needed today. God no longer needs to demonstrate to the Jews that He also redeemed His elect from every tribe, language, and nation; and, He no longer needs to demonstrate His power and authority through His apostles and prophets because His Word is complete.
The evidence that God has saved a sinner, whether Jew or Gentile, is a changed heart demonstrated by repentance from sin, love for God and neighbor, and pursuit of holiness. Any teaching requiring speaking in tongues as evidence of receiving the Holy Spirit is not only a misinterpretation of Scripture and creates an unbiblical, tiered Christianity, but it is damaging to the assurance of salvation in the life of the believer. Perhaps most sadly, is that many who “speak in tongues” having been baptized by “holy fire” have actually never come into a saving relationship with Jesus Christ, have never been truly baptized by the Holy Spirit (regeneration), and are still dead in their sins.
For further reading, see Holiness vs. the “Holiness Movement”.
Also see Tom Pennington’s message from Strange Fire, A Case for Cessationism.