Finished but Not Finished
This idea that before Pentecost it is surely true that Jesus finished any need of sacrifice for sin. He declared it so in John 19:30 when he employed the term "tetelestai." This term that is translated "it is finished" was a term used in commerce to indicate that a bill had been paid in full. So, it is sure that Jesus' work on the cross made a finish for the payment of sin.
But, the not finished part of Jesus work was his baptizing in/by/with The Holy Spirit. Again, this the other feature of what John the baptizer had declared was the ministry of Jesus. John's declaration of Jesus as baptizer with the Holy Spirit is surely evidenced by Jesus' interaction with one of the top religious leaders of his day: Nicodemus.
Jesus reveals to Nicodemus that one cannot be a part of God's kingdom unless one is born of The Spirit. Jesus is clear to reveal that The Spirit must be active in one's life for them to part of the Kingdom of God (John 3:5)
Think of what Jesus alleges here to a religious leader. One must be born of The Spirit not just born of a specific lineage of Abraham. God's kingdom was a kingdom of The Spirit and thereby an international, interracial reality. All who experience Jesus' baptism of the Spirit. are his followers
This seems to be precisely what happened on Pentecost. People were no longer members of God's kingdom because they were Abraham's children; people were members of God's kingdom because they had been born of The Spirit. In fact, it is The Spirit's renewal that made the follower's of Jesus an international experience. No longer was it diet or lineage but The Spirit of God residing in people.
The Gospel is for the whole world and all people.
REFLECT: What importance of the Holy Spirit have you heard of in your journey with Jesus? How have you seen the Spirit bring people of different backgrounds into following Jesus?