The shepherd in the parable takes any amount of trouble to seek out the one lost sheep. He cannot rest as long as even one of a hundred is lost in the wilderness. Further, the shepherd is portrayed as celebrating the joy of recovering that which has been lost.
The parable portrays before us the image of a God who is merciful and gracious and who takes the initiative to seek out the lost. It means that in what Jesus does to ‘sinners and outcasts’ God himself is manifesting his mercy, gracious concern and initiative for those who are ‘lost.’ Jesus will later describe his ministry in the following words “For the Son of Man came to seek and save the lost” (Lk 19: 10). The parable conveys that same mission of Jesus.
God is not only willing and persistent in searching for even one of his lost children, but rejoices and celebrates the recovery of the lost. Luke 15: 9 adds a new note: the repentance on the part of the sinner is a reason for the heavenly joy. God’s “for-given” love, that is, his love offered in advance manifested by his initiative of gracious concern is what brings about repentance in the sinner. The parable thus emphasizes God’s joy of “searching till he finds” the sinner and the heavenly joy over repentant sinner. All this takes place now through the ministry of Jesus to the sinners and outcasts of Palestine.