The Parable of the Lost Sheep tells the story of one shepherd who, having lost one of his one-hundred sheep, abandons the remainder of his flock to go searching for it. Finding it, he rejoices.
That is the essential plot to the three versions of the story – but there are some variations. First, the context within which the story is told in Matthew and Luke and Thomas are different: Matthew has it set as response to a question concerning care for God’s little ones; Luke places it as a rejoinder to the Pharisees concerning Christ’s association with sinners. Meanwhile Thomas has it as an elaboration of a description of Christ as being the way for those who are lost.
Second, only Matthew has the parable begin with a question ‘What do you think?’, the other gospels have it begin with some statement. Matthew has the sheep itself go astray; in Luke the shepherd loses it. In Matthew the sheep may be one of the little ones; in the other gospels it is only one of the flock. In Matthew the shepherd rejoices alone; in Luke he calls friends to join in the rejoicing – this means a different emphasis for finding and for celebration, respectively.
Finally, the implied object of the parable changes: in Matthew, it is one of the faithful who has gone astray; in Luke it seems meant to refer to a sinner.
Taken together, these imply a more didactic purpose for the parable in Matthew. It is a parable expressly for the governance of community in the midst of teachings about who will be greatest in the kingdom, where the little ones will be, how to deal with those members who sin and lead others astray. The opening question would be a pedagogical tool, and the sheep itself going astray clearly makes it more similar to a human being – in the sense of going astray as a willful action. Finally, as part of its unique emphasis on finding again, Matthew leaves the shepherd to rejoice alone at the end. The point is that those in the community should do for those who stray just what God would do: find them again.
To preach the Parable of the Lost Sheep in Matthew would be to reflect on God’s exorbitant fidelity to God’s followers and the implied innocence of those who are deceived; to go astray is more nearly to be lead astray and paired with the previous teaching concerning those who lead the little one astray the blame is quite clearly on the deceiver rather than the lost.
The sheep itself is not a fault and is to be found and restored to the community. The success of this endeavor is not guaranteed; sheep are sometimes permanently loss. But the possibility implies responsibility for and from everyone in the community, especially if we remember the pastoral tone of the beatitudes in the same gospel, and the nature of pastoral care in Matthew. The shepherd is alone in Matthew because the shepherd is the believing community itself. The sheep is worthy of rejoicing because it is one of God’s own faithful, and it is the will of God that no one perish.