News spreads that the Gentiles also had received the word of God. As a result, when Peter went up to Jerusalem, the circumcision party criticised him. At this point, their attitude towards others receiving what they had received from then Lord was less than excellent. They are stuck in the mindset that to become a believer in Jesus you must first become Jewish, and they’re mad that Peter went to uncircumcised men and ate with them.
Peter gives them a replay of what happened whilst he was in Joppa (vv.4-15) and explains the whole thing as God teaching them that there is no distinction now in terms of who can come to Him. The proof of this, Peter says, is that the Holy Spirit fell on them just as on us at the beginning (vv.16-17, cf. Acts 1.5). The miraculous and spectacular coming of the Spirit in Acts 2 and Acts 10 was making a point: the same God, with the same gifts, the same Spirit, the same salvation, is now available to all.
The same is true for you and for me: God has granted repentance that leads to life no matter who we are or where we are from (v.18b). It is no longer essential to be part of a certain ethnic heritage or to take on the customs and practices of that group in order to have access to God. Through the death and resurrection of Jesus, all can have sins atoned for and all can have eternal life (John 3.16). All have access to the Father through the sacrifice of the Son and all have the same Spirit living in them. If you have believed in Jesus as Lord and Saviour then the same Spirit that fell on the believers in Acts 2 and on the Gentiles in Acts 10 is the same Spirit that now lives in you (1 Corinthians 6.19). This turns reading the book of Acts into something inherently personal. It’s the beginning of our church, it’s the establishment of our faith, it is where we see our God working in our history. Then, as we read these things, our reaction will be like the brothers and sisters: they glorified God!