On the day of Pentecost (Acts 2) the Holy Spirit enabled the apostles to speak in foriegn languages:
4 They were all filled with the Holy Spirit, and began to speak with other languages, as the Spirit gave them the ability to speak.
After believers in Ephesus are baptised, they are also able to speak foreign languages after receiving the Holy Spirit:
6 When Paul had laid his hands on them, the Holy Spirit came on them and they spoke with other languages and prophesied.
In his speech on the day of Pentecost, the apostle Peter points out to his audience the seriousness of what they have done in being involved in the crucifixion of Jesus:
36 “Let all the house of Israel therefore know certainly that God has made him both Lord and Christ, this Jesus whom you crucified.”
As a result they are desperate to do something about their guilt:
37 Now when they heard this, they were cut to the heart, and said to Peter and the rest of the apostles, “Brothers, what shall we do?”
In response Peter tells them how they can be forgiven:
38 Peter said to them, “Repent, and be baptised, every one of you, in the name of Jesus Christ for the forgiveness of sins, and you will receive the gift of the Holy Spirit.
Peter tells them that by being baptised, they can have forgiveness of sins and the gift of the Holy Spirit. The gift of the Holy Spirit was evidence of their forgiveness for their terrible sin.
Earlier on in his speech, Peter says that the giving of the Holy Spirit is a a witness to the resurrection of Jesus:
32 This Jesus God raised up, to which we all are witnesses. 33 Being therefore exalted by the right hand of God, and having received from the Father the promise of the Holy Spirit, he has poured out this, which you now see and hear.
The Holy Spirit was given later on by the apostles Peter and John:
14 Now when the apostles who were at Jerusalem heard that Samaria had received the word of God, they sent Peter and John to them, 15 who, when they had come down, prayed for them, that they might receive the Holy Spirit; 16 for as yet he had fallen on none of them. They had only been baptised in the name of Christ Jesus. 17 Then they laid their hands on them, and they received the Holy Spirit.
The Holy Spirit was given as a witness at the conversion of Cornelius to show that the Gentiles (non-Jews) could now be baptised:
44 While Peter was still speaking these words, the Holy Spirit fell on all those who heard the word. 45 They of the circumcision who believed were amazed, as many as came with Peter, because the gift of the Holy Spirit was also poured out on the Gentiles. 46 For they heard them speaking in other languages and magnifying God.
Then Peter answered, 47 “Can anyone forbid these people from being baptised with water? They have received the Holy Spirit just like us.”
Conclusion
The gift of the Holy Spirit:
- enabled the apostles and other believers to speak in foreign languages
- was given as a witness:
- to their forgiveness for being involved in the crucifixion of Jesus Christ
- to the resurrection of Jesus
- that God approved of non-Jews being baptised
- was given by the apostles