The parable that follows teaches the same lesson as the preceding verse. It is found in Luke 15:1-7, with some variations, delivered to a different audience and under different circumstances, as Jesus often repeated his instructions and teaching according to the occasion.
How think ye? What say ye to the following case? Thus the Lord engages the disciples' attention. An hundred sheep. A round number, representing a considerable flock. If but one of these stray, the good Shepherd regards only the danger and possible destruction of this wanderer, and puts aside every other care in order to secure its safety.
The ninety and nine. These must be left for a time, if he is to conduct the search in person. It may he that some idea of probation is here intended, as when Jesus let the disciples embark on the lake while he himself remained on the shore.
Many of the Fathers interpret the ninety-nine as representing the sinless angels, the lost sheep as man, to seek and save whom Christ left heaven, i.e. became incarnate. This, indeed, may be a legitimate application of the parable, but is inexact as an exposition of the passage, which regards the whole flock as figuring the human race.
The sheep that remained safe and true to their Master are the righteous; the errant are the sinners, which, however few, are the special care of the merciful Lord. Into the mountains ( ἐπι Ì τα Ì ὐ ìρη).
There is much doubt whether these words are to be joined with goeth ( πορευθει Ìς), as in both our versions, or with leave ( ἀφει Ìς), as in the Vulgate, Nonne relinquit nonaginta novem in montibus?
In the former case we have a picture of the toil of the shepherd traversing the mountains in search of the lost. But this does not seem to be the particular point contemplated, nor is any special emphasis assigned to this part of the transaction.
In the parable as recounted by St. Luke (Luke 15:4), we read, "Doth he not leave the ninety and nine in the wilderness, and go?" So here it is best to render, Doth he not leave the ninety and nine upon the mountains?
The shepherd is not regardless of the safety and comfort of the flock during his temporary absence; he leaves them where they are sure to find pasture, as they roam over ( ἐπι Ì with accusative) the hill tops, which, catching clouds and dew, are never without fresh grass.
So Psalms 147:8, "Who covereth the heaven with clouds, who prepareth rain for the earth, who maketh grass to grow upon the mountains." Seeketh. The lost sheep would not return of itself. Such erring souls Jesus seeks by the inspiration of his Spirit, by allowing distress and sorrow, by awakening conscience and memory, by ways manifold which may lead the sinner to "come to himself."