Luke 11:3

Or the bread of souls is the Divine power, bringing the everlasting life which is to come, as the bread which comes out of the earth preserves the temporal life. But by saying "daily," He signifies the Divine bread which comes and is to come, which we seek to be given to us daily, requiring a certain earnest and taste of it, seeing that the Spirit which dwells in us hath wrought a virtue surpassing all human virtues, as chastity, humility, and the rest.

(in Reg. brev. ad inter. 252.) As if He said, For thy daily bread, namely, that which serves for our daily wants, trust not to thyself, but fly to God for it, making known to Him the necessities of thy nature.

(Hom. 23. in Matt.) We must then require of God the necessities of life; not varieties of meats, and spiced wines, and the other things which please the palate, while they load thy stomach and disturb thy mind, but bread which is able to support the bodily substance, that is to say, which is sufficient only for the day, that we may take no thought of the morrow. But we make only one petition about things of sense, that the present life may not trouble us.

Now perhaps some think it unfit for saints to seek from God bodily goods, and for this reason assign to these words a spiritual sense. But granting that the chief concern of the saints should be to obtain spiritual gifts, still it becomes them to see that they seek without blame, according to our Lord's command, their common bread. For from the fact that He bids them ask for bread, that is daily food, it seems that He implies that they should possess nothing, but rather practise an honourable poverty. For it is not the part of those who have bread to seek it, but rather of those who are oppressed with want.

(App. Serm. 84..) In the Greek the word is ἐπιούσιον, that is, something added to the substance. (supersubstantialem) It is not that bread which goes into the body, but that bread of everlasting life, which supports the substance of our soul. But the Latins call this "daily" bread, which the Greeks call "coming to." If it is daily bread, why is it eaten a year old, as is the custom with the Greeks in the east? Take daily what profits thee for the day; so live that thou mayest daily be thought worthy to receive. The death of our Lord is signified thereby, and the remission of sins, and dost thou not daily partake of that bread of life? He who has a wound seeks to be cured; the wound is that we are under sin, the cure is the heavenly and dreadful Sacrament. If thou receivest daily, daily does "To-day" come unto thee. Christ is to thee To-day; (Heb. 13:8.) Christ rises to thee daily.