4 Bible Verses about Lost Sheep

I have gone astray like a lost sheep; seek thy slave; for I have not forgotten thy commandments.

For ye were as sheep that had gone astray, but are now converted unto the Shepherd and Bishop of your souls.

Verily, verily, I say unto you, He that enters not by the door into the sheepfold, but climbs up some other way, the same is a thief and a robber. But he that enters in by the door is the shepherd of the sheep. To him the porter opens, and the sheep hear his voice, and he calls his own sheep by name and leads them out.read more.
And when he puts forth his own sheep, he goes before them; and the sheep follow him, for they know his voice. And they will not follow a stranger, but will flee from him, for they do not know the voice of strangers. Jesus spoke this parable unto them, but they did not understand what it was that he spoke unto them. Then said Jesus unto them again, Verily, verily, I say unto you, I AM the door of the sheep. All that ever came before me are thieves and robbers, but the sheep did not hear them. I AM the door; whosoever enters in by me shall be saved and shall go in and out and find pasture. The thief comes not but for to steal and to kill and to destroy the sheep; I am come that they might have life and that they might have it in abundance. I AM the good shepherd; the good shepherd gives his life for the sheep. But the hireling, who is not a shepherd, whose own the sheep are not, sees the wolf coming and leaves the sheep and flees; and the wolf catches them and scatters the sheep. The hireling flees because he is a hireling, and the sheep do not belong to him. I AM the good shepherd, and know my sheep and am known of mine. As the Father knows me, even so I know the Father, and I lay down my soul for the sheep. And I have other sheep which are not of this fold; it is expedient that I bring them also, and they shall hear my voice, and there shall be one fold and one shepherd. Therefore does my Father love me, because I lay down my soul that I might take it again. No man takes it from me, but I lay it down of myself. I have power to lay it down, and I have power to take it again. This commandment I have received of my Father. There was a division therefore again among the Jews for these words. And many of them said, He has a demon and is beside himself; why do ye hear him? Others said, These are not the words of him that has a demon. Can a demon open the eyes of the blind? And they celebrated the dedication in Jerusalem, and it was winter. And Jesus walked in the temple in Solomon's porch. Then the Jews came round about him and said unto him, Until when wilt thou hold our soul in suspense? If thou art the Christ, tell us plainly. Jesus answered them, I have told you, and ye do not believe; the works that I do in my Father's name, they bear witness of me. But ye believe not because ye are not of my sheep, as I said unto you. My sheep hear my voice, and I know them, and they follow me;

What do you think? If a man had a hundred sheep and one of them went astray, would he not leave the ninety-nine and go into the mountains and seek that which is gone astray?