What does Acts 2:43 mean?

Throughout the Bible, God has granted His messengers the ability to perform miracles in order to validate that their message is from Him. The point of ministry is never the miracle itself, but the message (Mark 1:36–38).

The disciples have performed miracles before, and they know what comes after. Early on, Jesus sent them out to heal, cast out demons, and exhort people to repent of their sins (Mark 6:7–13). They had seen what happened to Jesus when He performed miracles: He was mobbed (Mark 4:1). They got a taste of this, too—when Jesus took them on a boat to find some time away and the people saw them leave and raced so hard a crowd had formed before they landed (Mark 6:30–34).

This time, they are prepared. They have received the Holy Spirit who gives them power (Acts 1:8) but also wisdom (John 14:26). And that same Holy Spirit is working in the hearts of the people the apostles meet (John 16:8–11).

"Wonder" is from the Greek root word teras. It is a miracle that reveals a hidden truth, like how the transfiguration revealed Jesus' glory and deity (Mark 9:2–13). "Signs" is from the Greek root word semeion. The sign is that the person who performs the miracles is special and chosen by God. A good example is when Paul suffers no ill effect after being bitten by a viper. At first, the local people think he is being cursed by the gods for a terrible offense. When he lives, they still assume he has a divine connection, but still misinterpret it, at first (Acts 28:1–6).