The liturgy interprets for us the language of Jesus’ heart, which tells us above all that God is the shepherd of mankind, and so it reveals to us Jesus’ priesthood, which is rooted deep within his heart; so too it shows us the perennial foundation and the effective criterion of all priestly ministry, which must always be anchored in the heart of Jesus and lived out from that starting-point.
The most important of those texts in today’s liturgy is Psalm 23(22) – "The Lord is my shepherd" – in which Israel at prayer received God’s self-revelation as shepherd, and made this the guide of its own life. "The Lord is my shepherd, I shall not want": this first verse expresses joy and gratitude for the fact that God is present to and concerned for humanity. The reading from the Book of Ezechiel begins with the same theme: "I myself will look after and tend my sheep" (Ez 34:11). God personally looks after me, after us, after all mankind. I am not abandoned, adrift in the universe and in a society which leaves me ever more lost and bewildered. God looks after me. He is not a distant God, for whom my life is worthless.
-Pope Benedict XVI