Matthew 6:11

Give us this day our daily bread--The compound word here rendered "daily" occurs nowhere else, either in classical or sacred Greek, and so must be interpreted by the analogy of its component parts. But on this critics are divided. To those who would understand it to mean, "Give us this day the bread of to-morrow"--as if the sense thus slid into that of Luke "Give us day by day" (Luk 11:2, as BENGEL, MEYER, &c.) it may be answered that the sense thus brought out is scarcely intelligible, if not something less; that the expression "bread of to-morrow" is not at all the same as bread "from day to day," and that, so understood, it would seem to contradict Mat 6:34. The great majority of the best critics (taking the word to be compounded of ousia, "substance," or "being") understand by it the "staff of life," the bread of subsistence, and so the sense will be, "Give us this day the bread which this day's necessities require." In this case, the rendering of our authorized version (after the Vulgate, LUTHER and some of the best modern critics)--"our daily bread"--is, in sense, accurate enough. (See Pro 30:8). Among commentators, there was early shown an inclination to understand this as a prayer for the heavenly bread, or spiritual nourishment; and in this they have been followed by many superior expositors, even down to our own times.

— Jamieson-Fausset-Brown Commentary (public domain)