Cornelius a Lapide has an excellent explanation about it
You ask what is supersubstantial bread? I reply the Greek is ε̉πιούσιον, which is found only here and in S. Luke xi. 3. 1. Angelus Caninius (lib. de Nom. Heb. N. Test.) translates to-morrow’s bread, for ε̉πιουσια ημερα is often put for the following day. He would paraphrase the petition thus, “As on the day of preparation, or Friday, the Hebrews in the wilderness collected manna for the Sabbath, on which day they were to rest, so do Thou, 0 Lord, give us this day bread for to-morrow, for we are not solicitous for anything beyond, but after to-morrow we await, and as it were prepare ourselves for the Lord’s Resurrection, and the eternal jubilee. Therefore, we collect our baggage, and only ask for bread for to-morrow. It is in favour of this that S. Jerome writes that the Hebrew Gospel of the Nazarenes reads מחר machar, i.e. “for tomorrow.” Whence S. Athanasius (Tract. de Incarn. Verb.) thinks that we here ask for the Holy Spirit, who is the Divine Bread, whom we hope to feed upon and enjoy in Heaven, and whose first-fruits we receive and taste in the Eucharist.
- S. Jerome explains
ε̉πιούσιον by περιούσιον, that is principal, glorious, excellent. Symmachus translates elect, or that which is above all substances, and is superior to all creatures. So also Cassian (Collat. 9. 20), Cyril (Cat. Mystag. 5), and S. Ambrose (lib. 5, de Sacrament. c. 4), who by this bread understands the Eucharist which in Zech. ix. is called “the corn of the elect.” (Vulg.)
- Literally,
ε̉πιούσιος, means that which pertains to substance, say substantial, essential, that which is for the preservation of man’s life and substance, as often as is necessary. So S. Chrysostom, Theophylact, and S. Basil, as well as many others, who with Suidas interpret ε̉πιούσιον, as ε̉πὶ τὴν ημω̃ν ου̉σίαν καὶ τροφὴν ε̉παρκου̃ται, or that which is congruous to, and suffices for, our substance and nutrition, that which subserves, not pleasure but necessity, that which is not too delicate or abundant but frugal and moderate, i.e. daily. Hence the Syriac has the bread of our need; Arabic, bread sufficient. So, also the Egyptian, Ethiopic, and Persian versions. So also the Fathers who lived before S. Jerome’s version, such as SS. Cyprian, Ambrose, Augustine, translate daily bread. And the Church in the Breviary and Missal uses the same ancient translation, and teaches the faithful to pray, Give us this day our daily bread.
S. Jerome, who, at the bidding of Pope Damasus, corrected the Latin version of the New Testament, in accordance with the Greek, in this place substituted supersubstantial for daily, to bring the passage into accord with the Greek.
This supersubstantial, or daily bread, is a parallel expression to the Hebrew דבר יום davar yom, “the thing, or matter of a day.” For Christ forbids us to be anxious about the morrow, in which it is uncertain whether or not we shall be alive. “He would,” says S. Chrysostom, “that we should be always girded, and provided, as it were, with wings of faith, by which we may fly heavenward, and give no greater indulgence to nature than necessary use demands.” Again, S. Jerome’s reason for translating ε̉πιούσιον literally, by supersubstantial, was to indicate that in this petition we ask above all for heavenly bread, such as we receive in the Eucharist.
- You ask what is this special supersubstantial, or daily bread. Calvin (lib. 3, Instit. c. 20, 44), and Philip Melancthon, in his Commonplaces, tit. de Invocat., understand it of corporeal food only. Some Catholics understand it to mean only spiritual food. Certainly SS. Jerome, Cyril, Ambrose, Cassian, speak expressly of this alone, in the passages about to be cited. But I say that this bread is both material, for the sustenance of the body, and spiritual and heavenly bread, suitable for the nourishment of the soul, such as the word of God and the Eucharist. We have need of both, and therefore we ought to ask for both, and for the latter so much more earnestly than the former, as the soul is superior to the body. And this is denoted by the word supersubstantial, which S. Jerome explains to mean superexcellent, surpassing all created substances, because, as Cassian says, “the sublimity of its magnificence and its sanctity is superior to that of the whole creation.” And for this reason, in the Greek, the definite article is added, doubled in truth, τὸν άρτον τὸν ε̉πιούσιον, the bread the supersubstantial. As though it were said, “Give us bread not common, but celestial and divine.” Christ alludes to the manna given to the Hebrews, which was a type of the Eucharist. For of manna, it is said in Ps. lxxviii. 24, “He gave them bread from heaven.” “Man did eat angels’ food.” Thus, therefore, manna was food ε̉πιούσιος, i.e., heavenly and angelic; but much more is the Eucharist. Whence in Wisd. xix. 20, both are called in Greek Ambrosia, which is said by the poets to be the food of the gods. S.Ambrose calls the Eucharist this supersubstantial bread. “If,” he says, “this be daily bread, why do you receive it only once a year? So live that you may be fit to receive it daily.” Thus the first Christians were accustomed to communicate daily, as is plain from Acts ii. 46. And S. Cyprian (de Orat. Domin.) says, “We ask that this bread may be daily given us, lest we, who are in Christ and daily receive the food of the Eucharist, by the intervention of some grave fault, by abstaining and not communicating, should be kept back from the heavenly Bread, and separated from the Body of Christ, when He Himself has admonished us saying, ‘I am the Bread of life, Who came down from Heaven. If any man shall eat of My Bread he shall live for ever.’” (S. John vi.)
