Alcuin of York — as excerpted in the Catena Aurea on John 6:22-27

“When, through the hand of the priest, thou receivest the Body of Christ, think not of the priest which thou seest, but of the Priest thou dost not see. The priest is the dispenser of this food, not the author. The Son of man gives Himself to us, that we may abide in Him, and He in us. Do not conceive that Son of man to be the same as other sons of men: He stands alone in abundance of grace, separate and distinct from all the rest: for that Son of man is the Son of God, as it follows, For Him hath God the Father sealed. To seal is to put a mark upon; so the meaning is, Do not despise Me because I am the Son of man, for I am the Son of man in such sort, as that the Father hath sealed Me, i. e. given Me something peculiar, to the end that I should not be confounded with the human race, but that the human race should be delivered by Me.”