Matthew 4:4

But he answered and said, It is written-- (Deu 8:3). Man shall not live by bread alone--more emphatically, as in the Greek, "Not by bread alone shall man live." but by every word that proceedeth out of the mouth of God--Of all passages in Old Testament Scripture, none could have been pitched upon more apposite, perhaps not one so apposite, to our Lord's purpose. "The Lord . . . led thee (said Moses to Israel, at the close of their journeyings) these forty years in the wilderness, to humble thee, and to prove thee, to know what was in thine heart, whether thou wouldest keep His commandments, or no. And He humbled thee, and suffered thee to hunger, and fed thee with manna, which thou knewest not, neither did thy fathers know; that He might make thee know that man doth not live by bread only," &c., "Now, if Israel spent, not forty days, but forty years in a waste, howling wilderness, where there were no means of human subsistence, not starving, but divinely provided for, on purpose to prove to every age that human support depends not upon bread, but upon God's unfailing word of promise and pledge of all needful providential care, am I, distrusting this word of God, and despairing of relief, to take the law into My own hand? True, the Son of God is able enough to turn stones into bread: but what the Son of God is able to do is not the present…

— Jamieson-Fausset-Brown Commentary (public domain)