58 And that we may observe that divine grace rather than human works in priests, of the many rods which Moses had received according to the Tribes, and had laid up, that of Aaron alone blossomed. And so the people saw that the gift of the Divine vocation is to be looked for in a priest, and ceased from claiming equal grace for a human choice though they had before thought that a similar prerogative belonged to themselves. But what else does that rod show, but that priestly grace never decays, and in the deepest lowliness has in its office the flower of the power committed to it, or that this also is refered to in mystery? Nor do we think that it was without a purpose that this took place near the end of the life of Aaron the priest. It seems to be shown that the ancient people, full of decay through the oldness of the long-continued unfaithfulness of the priests, being fashioned again in the last times to zeal in faith and devotion by the example of the Church, will again send forth with revived grace its flowers dead through so many ages.
Source: Letters (New Advent)