Charles Wesley began one of the Methodist Church's favorite hymns with this line: "Come Holy Ghost, Our Hearts Inspire." Of course, tradition now uses the alternate term, "Holy Spirit." Wesley called it the "fountain of life and love." And so it is. Once we experience the Holy Spirit, we know it is exactly that: the source of life and love. The giving of that Spirit into the lives of us all is the point of this passage.
Actually, there's a bit of politics indigenous to the time and place involved here, also. The Jews were surprised and perhaps upset that Gentiles should receive what they expected should be exclusively theirs. However, most of them quickly accommodated themselves to the universal gift of the Spirit as Peter made it plain that in fact it was God who gave the gift and that …