The superessential bread is the body and blood of the Lord, which differs as much from the word of God as does the sun from a ray.
In divine Communion, the Sun that is the whole God-man enters into, mixes with, and leavens the whole man, being He Who illumines, enlightens, and sanctifies all of the powers and senses of the soul and body of man, and refashions him from corruption to incorruption.
Thus the words “superessential bread” primarily and for an especial reason refer to the divine Communion of the all-immaculate body and blood of our Lord Jesus Christ, for it preserves and sustains the essence of the soul, and gives it the strength to do the Master’s commandments and everything else, as our Lord says: “For My flesh is meat indeed, and My blood is drink indeed” (Jn. 6:55), which is to say, My flesh is true food, and my blood is true drink.
If someone is in doubt as to how the body of our Lord is called superessential bread, let him listen to what the sacred teachers of our Church say concerning this.
[…] St. Isidore Pelousiotes says: “The prayer which the Lord taught does not contain anything earthly, but everything is heavenly and looks to the profit of the soul, even that which appears to be unimportant and sensible. And it is the opinion of many wise men that the Lord said this prayer for the following reason: in order to teach in a special way about the divine word and bread which nourishes the bodiless soul and which, in some way, is mixed and infused into the essence of the soul. For this reason it is also called superessential bread, inasmuch as the word ‘essence’ is more becoming of the soul than the body.”
[…] The divine Maximos says: “For if we live in the way we have prayed, to nourish our souls and to maintain the good state which we have been granted we will receive the superessential and life-giving bread, that is, the Word, Who said: I am the bread which came down from heaven and gives life to the world (cf. Jn. 6:41, 33). He becomes everything for us in proportion to the virtue and wisdom with which we have been nourished.”
In other words, living according to the words of the Lord’s Prayer, let us receive the Son and Word of God as the superessential bread, as vital food for our souls, and as a safeguard for the goods which have been granted to us. Moreover, the Lord said that He is the bread which came down from the heavens and gives life to the world. However, this occurs within each person who receives Him according to the virtue and knowledge which he has.
Nicodemus the Hagiorite (1749-1809): Explanation of the Lord’s Prayer.