Acts 2

38 So Peter said to them: "Repent and be baptized, each one of you, upon the name of Jesus Christ,*This is the first use of the title, Jesus Christ, after the Gospels; the Lord had Himself inaugurated the title fifty days before (John 17:3)—it affirms that Jesus is the Messiah. Anyone being baptized upon that name would be publicly declaring allegiance to Jesus as the Messiah. Notice that Peter promises forgiveness of sin and the gift of the Holy Spirit to any who enter into that commitment. for forgiveness of sins, and you will receive the gift of the Holy Spirit.