What does Acts 2:40 mean?

Earlier this very morning, the church was born as the Holy Spirit came to indwell 120 of Jesus' followers in Jerusalem, giving them the ability to speak in foreign languages and dialects (Acts 2:1–4). A large crowd of faithful Jews and proselytes from as far away as Rome, Libya, and Mesopotamia hear the Jesus-followers and are astonished (Acts 2:5–13). Peter explains that Jesus of Nazareth, who the Jewish nation condemned and executed, is the Messiah sent by God. Even more, He was resurrected by God and offers forgiveness and life to those who believe in Him (Acts 2:14–38).

Now, one of the basic tenets of the church is being established: that the church is a place where those more knowledgeable about Jesus teach those who are younger in the faith. As a result of the work of the Holy Spirit, as He empowers Peter's words, three thousand members of the crowd will call on Jesus' name and be saved (Acts 2:41). Many will stay in Jerusalem and create a new community dedicated to "the apostles' teaching and the fellowship, to the breaking of bread and the prayers" (Acts 2:42).

"Bore witness" is from the Greek root word diamartyromai and means "to attest to and confirm a message." "Exhort" is from the Greek root word parakaleō, and means "to encourage someone to take action." This is closely related to the word Paraklētos, used by Jesus when referring to the Holy Spirit as a "helper" (John 14:16). The message of Jesus requires a response, and the response cannot come without the message (Romans 10:14).

Jesus had also declared that the generation is crooked (Matthew 17:17). The scribes make great shows to gain respect but turn around and act cruelly to the vulnerable (Mark 12:38–40). The people kill the prophets that would lead them into God's presence (Matthew 23:37). And all of Matthew 23 is a list of sins the Pharisees and scribes commit against God. Most of all, the Jewish leaders don't believe Jesus is the Son of God come to save them. But Jesus offers people an escape. No one is condemned to follow their culture or leaders in rejecting Jesus. Everyone is invited to repent of their sins and turn to God. It is why Jesus sent His disciples (Acts 1:8), and why all His followers are included in the Great Commission to "make disciples of all nations" (Matthew 28:19).