We often dwell on the Eucharist as continuous with the sacrifice of the Lord's Passion and death, and rightly so, as it is the sacrifice of salvation. But the Eucharist is also continuous with the mystery of the incarnation. When the eternal Word is revealed on our terms, what happens? A baby born away from home to a young couple of an obscure and occupied people, a rejected teacher, a gentle healer, a friend of the wrong people, a wrongly accused a tortured criminal, and finally, in the most sublime humility, a little piece of bread.
Like all the genuine spiritualities of Christian vocations, that of the priesthood is deeply Marian. The priest at Mass is something like her mirror image. She consented to the Word being conceived in her body that she might be the Mother of God who held the infant Jesus in her arms. The priest consents to the Body of Christ descending into his hands that he might receive Him into his body, and offer the same grace to the faithful.
O admirable heights and sublime lowliness! O sublime humility! O humble sublimity! That the Lord of the universe, God and the Son of God, so humbles Himself that for our salvation He hides Himself under the little form of bread! Look, brothers, at the humility of God and pour out your hearts before Him! Humble yourselves, as well, that you may be exalted by Him. Therefore, hold back nothing of yourselves for yourselves so that He Who gives Himself totally to you may receive you totally
--Francis of Assisi, Letter to the Entire Order.