April 11th
Book Four, Chapter 5
On the Dignity of the Sacrament, and of the Priestly State

If you had the purity of an angel, and the sanctity of St. John the Baptist, you would neither be worthy to receive nor to handle this Sacrament.  For this is not due to man's merits, that a man should consecrate and handle the Sacrament of Christ, and receive for food the bread of angels.  Great is the Mystery, and great the dignity of priests, to whom is given that which to the angels is not granted.  For priests alone, rightly ordained in the Church, have the power of celebrating and consecrating the Body of Christ.