Craig Keener carefully examines the New Testament Gospels and the book of Acts to provide a fuller understanding of what the Holy Spirit meant in the lives of early believers. Christianity did not arise in a vacuum, but rather it appropriated, modified, and utilized the Jewish understanding of the work of the Holy Spirit. By understanding the world in which Christianity emerged, we can better understand the earliest believers' experience of God's empowering and purifying Spirit. This paperback edition contains a new preface by the author.