It becomes obvious to anyone reading chapter 15 of Luke’s gospel that its three parables are woven together as a well-knit single unit having one common theme: the joy of finding what has been lost. The three parables – the Lost Sheep (Lk 15: 4-7); the Lost Coin (Lk 15: 8-10); and the Lost Son (the Prodigal Son) (Lk 15: 11-32) – may not have been uttered by Jesus one after another; they may have had different contexts. But as they now stand in the gospel they are quite artistically linked together. They portray a very distinctive image of Jesus. Therefore, some call this section the ‘heart of the Lukan gospel.’ Luke deliberately paints such a vivid image of God who is specially concerned with those who are despised by society and thus have become outcast that this section of the gospel, together with the subsequent sections till the end of the Lukan travel narrative has been styled as “the Gospel of the Outcast.”
The setting and the theme at the beginning of Luke 15 (Lk 15: 1-3) is important for the understanding of the parables. It echoes Luke 5: 29-32. Jesus is criticized by the Pharisees and the Scribes for welcoming sinners and tax collectors, the outcasts of Jewish society and for having table-fellowship with them. The former considered it as totally incompatible with their principle of ‘salvation by segregation from the outcasts’ (cf. Lk 5: 29-32). In the face of such cynical charges Jesus defends his ministry for as well as association with the outcasts. The three parables affirm the same fundamental truth of God’s concern for such persons and groups as are considered sinners and outcasts and who are described as the “lost” in these parables.