Jamieson, Fausset & Brown

I am the good shepherd--emphatically, and, in the sense intended, exclusively so (Isa 40:11; Eze 34:23; Eze 37:24; Zac 13:7). the good shepherd giveth his life for the sheep--Though this may be said of literal shepherds, who, even for their brute flock, have, like David, encountered "the lion and the bear" at the risk of their own lives, and still more of faithful pastors who, like the early bishops of Rome, have been the foremost to brave the fury of their enemies against the flock committed to their care; yet here, beyond doubt, it points to the struggle which was to issue in the willing surrender of the Redeemer's own life, to save His sheep from destruction.