While Peter was still speaking these words, the Holy Spirit came on all who heard the message. The circumcised believers who had come with Peter were astonished that the gift of the Holy Spirit had been poured out even on Gentiles. For they heard them speaking in tongues and praising God.
Then Peter said, “Surely no one can stand in the way of their being baptized with water. They have received the Holy Spirit just as we have.” So he ordered that they be baptized in the name of Jesus Christ. Then they asked Peter to stay with them for a few days.
The first Christians were Jews with a clear vision of God and lots of rules about spiritual washing and cleansing; what foods you can and cannot eat; and who you could relate to. They were incredibly suspicious of and kept their distance from non-Jews or Gentiles. At the beginning of Chapter 10, Peter has a dream, a vision telling him to preach to the Gentiles, to the spiritually ‘unclean’.