Jesus states the message of Luke to the global church today. Christ did not come for the clean and the religious, the upright and the educated—he came for those who know themselves to be lost. Throughout Luke we see Jesus welcoming outsiders into the blessings of grace, while those who appear to be insiders are shut out.
Jesus is portrayed in the book of Luke, Luke depicts Jesus in his short-lived ministry as deeply compassionate — caring for the poor, the oppressed, and the marginalized of that culture, such as Samaritans, Gentiles, and women. Whereas Matthew traces Jesus' genealogy to Abraham, father of the Jewish people, Luke goes back to Adam, parent of us all.
Luke's gospel is clearly written more for a gentile audience. Luke is traditionally thought of as one of Paul's traveling companions and it's certainly the case that the author of Luke was from those Greek cities in which Paul had worked.