John 10:17

Therefore doth the Father love me, because I lay down my life, that I may take it again.

I lay down ... that I may take ... Jesus here expressed his absolute freedom and authority both to die and to rise from the dead. There are three differences between Jesus' laying down his life for the sheep and that of the shepherds' doing so in the metaphor. These are: (1) Jesus' death is altogether voluntary, but not like the shepherd's involuntary death while fighting against a robber. The shepherd might indeed die, but not willingly. (2) Christ's death actually saves the sheep eternally, whereas the death of a shepherd would only hasten the death and destruction of the sheep. (3) Christ will lay down his life, but with a purpose of taking it up again, something no earthly shepherd could do.