Catechism of the Council of Trent: "Give us this day our daily bread"
Christ Is Our Spiritual Bread, Especially In The Holy Eucharist
Now Christ the Lord is that bread which is the food of the soul. I am, He says of Himself, the living bread which came down from heaven. It is incredible with what pleasure and delight this bread fills devout souls, even when they must contend with earthly troubles and disasters. Of this we have an example in the Apostles, of whom it is written: They, indeed, went into the presence of the council rejoicing. The lives of the Saints are full of similar examples; and of these inward joys of the good, God thus speaks: To him that overcometh, I will give the hidden manna.
But Christ the Lord is especially our bread in the Sacrament of the Eucharist, in which He is substantially contained. This ineffable pledge of His love He gave us when about to return to the Father, and of it He said: He that eateth my flesh, and drinketh my blood, abideth in me, and I in him, Take ye and eat: this is my body. For matter useful to the faithful on this subject the pastor should consult what we have already said on the nature and efficacy of this Sacrament.
The Eucharist is called our bread, because it is the food of the faithful only, that is to say, of those who, uniting charity to faith, wash away the defilement of their sins in the Sacrament of Penance, and mindful that they are the children of God, receive and adore this divine Sacrament with all possible holiness and veneration.
Why The Holy Eucharist Is Called Our "Daily" Bread
The Eucharist is called daily (bread) for two reasons. The first is that it is daily offered to God in the sacred mysteries of the Christian Church and is given to those who seek it piously and holily. The second is that it should be received daily, or, at least, that we should so live as to be worthy, as far as possible, to receive it daily. Let those who hold the contrary, and who say that we should not partake of this salutary banquet of the soul but at distant intervals, hear what St. Ambrose says: If it is daily bread, why do you receive it yearly?
Exhortations
In the explanation of this Petition the faithful are emphatically to be exhorted that when they have honestly used their best judgment and industry to procure the necessary means of subsistence, they leave the issue to God and submit their own wish to the will of Him who shall not suffer the just to waver for ever. For God will either grant what is asked, and thus they will obtain their wishes; or He will not grant it, and that will be a most certain proof that what is denied the good by Him is not conducive either to their interest or their salvation, since He is more desirous of their eternal welfare than they themselves. This topic the pastor will be able to amplify, by explaining the reasons admirably collected by St. Augustine in his letter to Proba.
In concluding his explanation of this Petition the pastor should exhort the rich to remember that they are to look upon their wealth and riches as gifts of God, and to reflect that those goods are bestowed on them in order that they may share them with the indigent. With this truth the words of the Apostle, in his First Epistle to Timothy, will be found to accord, and will supply parish priests with an abundance of matter wherewith to elucidate this subject in a useful and profitable manner.