Who are the people of God? Luke's purposes in Acts are to identify the Church, to establish the legitimacy of its gospel and to demonstrate that God was an active force in history. He shows that the communities of Jewish and Gentile Christians are the true heirs of God's promises to Israel. This is a theological interpretation of the history of the Church within history: Luke is an artist, a narrator rather than a systematic theologian, but he writes about the roles of God, Christ and the Holy Spirit and of the Church.