3 Bible Verses about Lost Sheep

For you were like sheep that had gone astray; but now you have returned to the shepherd and bishop of your souls.

Verily, verily I say to you, he that goes not through the door into the sheepfold, but climbs up some other way, he is a thief, and a robber. But he that enters through the door, is the shepherd of the sheep. To him the door-keeper 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 his own sheep out, he goes before them; and the sheep follow him; for they know his voice. And a stranger they will not follow, but will flee from him; for they know not the voice of strangers. This parable spoke Jesus to them; but they knew not the meaning of the things which he spoke to them. Therefore Jesus spoke again to them: Verily, verily I say to you, I am the door of the sheep. All that came before me were thieves and robbers; but the sheep did not hear them. I am the door: if any one enters through me, he shall be saved; and he shall go in and out, and find pasture. The thief comes only to steal and kill and destroy. I have come that they may have life, and have it in abundance. I am the good shepherd: the good shepherd lays down his life for the sheep. But he that is a hireling, and not the shepherd, to whom the sheep do not belong, sees the wolf coming, and leaves the sheep, and flees; and the wolf catches the sheep, and scatters them. The hireling flees because he is a hireling, and cares not for the sheep. I am the good shepherd, and I know my sheep, and am known by mine. As the Father knows me, I also know the Father, and I lay down my life for the sheep. And other sheep I have, which are not of this fold; those, also, must I bring, and they will hear my voice: and there shall be one flock, one shepherd. For this reason, my Father loves me, because I lay down my life that I may take it again. No one takes it from me, but I lay it down of myself. I have authority to lay it down, and I have authority to take it again. This commandment I have received from my Father. Again, therefore, there was a division among the Jews, on account of these words. And many of them said: He has a demon, and is mad; why do you hear him? Others said: These are not the words of one that has a demon. Can a demon open the eyes of the blind? And the feast of the dedication was celebrated in Jerusalem, and it was winter: and Jesus was walking in the temple, in Solomon's porch. Then the Jews came round him, and said to him: How long do you keep us in suspense? If you are the Christ, tell us plainly. Jesus answered them: I have told you, and you do not believe. The works which I do in my Father's name, these testify of me. But you believe not, because you are not of my sheep. As I said to you, my sheep hear my voice, and I know them, and they follow me:

What think you? If a man have a hundred sheep, and one of them go astray, does he not leave the ninety-nine, and go into the mountains, and seek for that which has gone astray?