In John Chapter 10,
Jesus says, “Truly, truly I say to you, he who does not enter by the door into the fold of the sheep, but climbs up some other way, he is a thief and a robber. But he who enters by the door is a shepherd of the sheep. To him the doorkeeper opens, and the sheep hear his voice, and he calls his own sheep by name and leads them out. When he puts forth all his own, he goes ahead of them, and the sheep follow him because they know his voice. A stranger they simply will not follow, but will flee from him because they do not know the voice of strangers.” This figure of speech Jesus spoke to them, but they did not understand what those things were which He had been saying to them.
So Jesus said to them again,
Truly, truly, I say to you, I am the door of the sheep. All who came before Me are thieves and robbers, but the sheep did not hear them. I am the door; if anyone enters through Me, he will be saved, and will go in and out and find pasture. The thief comes only to steal and kill and destroy; I came that they may have life and have it abundantly. I am the good shepherd; the good shepherd lays down His life for the sheep. He who is a hired hand, and not a shepherd, who is not the owner of the sheep, sees the wolf coming, and leaves the sheep and flees, and the wolf snatches them and scatters them. He flees because he is a hired hand and is not concerned about the sheep. I am the good shepherd, and I know My own and My own know Me, even as the Father knows Me and I know the Father; and I lay down My life for the sheep. I have other sheep, which are not of this fold; I must bring them also, and they will hear My voice; and they will become one flock with one shepherd. For this reason the Father loves Me, because I lay down My life so that I may take it up again. No one has taken it away from Me, but I lay it down on My own initiative. I have authority to lay it down, and I have authority to take it up again. This commandment I received from My Father.” [NASB Bible]