Dominica II post Pascha: "I am the Good Shepherd"

From the Holy Gospel according to John
John 10:11-16
At that time, Jesus said unto the Pharisees: "I am the Good Shepherd. The Good Shepherd giveth His life for His sheep." And so on.

Homily by Pope St. Gregory the Great.
14th on the Gospels
Dearly beloved brethren, ye have heard from the Holy Gospel what is at once your instruction, and our danger. Behold, how He Who, not by the varying gifts of nature, but of the very essence of His being, is Good, behold how He saith: I am the Good Shepherd. And then He saith what is the character of His goodness, even of that goodness of His which we must strive to copy: The Good Shepherd giveth His life for the Sheep. As He had foretold, even so did He; as He had commanded, so gave He example. The Good Shepherd gave His life for the sheep, and made His Own Body and His Own Blood to be our Sacramental Food, pasturing upon His Own Flesh the sheep whom He had bought.