Ezekiel 34:11
9 Therefore, you shepherds, listen to the Lord’s message. 10 This is what the Sovereign Lord says: Look, I am against the shepherds, and I will demand my sheep from their hand. I will no longer let them be shepherds; the shepherds will not feed themselves anymore. I will rescue my sheep from their mouths, so that they will no longer be food for them. 11 “‘For this is what the Sovereign Lord says: Look, I myself will search for my sheep and seek them out. 12 As a shepherd seeks out his flock when he is among his scattered sheep, so I will seek out my flock. I will rescue them from all the places where they have been scattered on a cloudy, dark day. 13 I will bring them out from among the peoples and gather them from foreign countries; I will bring them to their own land. I will feed them on the mountains of Israel, by the streams and all the inhabited places of the land.
Matthew 18:12
10 “See that you do not disdain one of these little ones. For I tell you that their angels in heaven always see the face of my Father in heaven. 12 What do you think? If someone owns a hundred sheep and one of them goes astray, will he not leave the ninety-nine on the mountains and go look for the one that went astray? 13 And if he finds it, I tell you the truth, he will rejoice more over it than over the ninety-nine that did not go astray. 14 In the same way, your Father in heaven is not willing that one of these little ones be lost. 15 “If your brother sins, go and show him his fault when the two of you are alone. If he listens to you, you have regained your brother.
Notes and References
"... In the Hebrew Bible, for the great majority of cases, the sheep represent Israel, as the “sheep of his pasture,” with the shepherd as God, or his representatives, the king or leaders. While some of these passages address the idyllic relationship between shepherd and flock, more commonly, the images are used to depict the afflictions suffered by the sheep, often at the hands of worthless shepherds ... The above metaphor pervades the Scriptures, but is most prominent in the account elaborated in Ezekiel 34, a passage that likely influenced Matthew considerably. The parable of the lost sheep may have been modified under its influence, and the “parable” of the sheep and the goats (Matthew 25:31-46) seemingly reflects the judgement between the strong and weak sheep at Ezekiel 34:17-22. Bammel finds echoes of Ezekiel 34 at both Matthew 8:34 and 10:6. To the latter passage, which will be discussed shortly, can likely be added the healing and feeding complex at 15:29-39 ... In possible dependence on Ezekiel 34, Matthew 18:12 features the editorial inclusion of “on the mountains” ..."
Cousland, J. R. C. The Crowds in the Gospel of Matthew (pp. 87-88) Brill, 2002