The famous reply of Jesus when tempted (Matthew 4:4) originally came from Deuteronomy 8:3, “…man does not live by bread alone, but man lives by every word that comes from the mouth of the LORD.” It is a profound truth, and vital for the Christian to understand. In the original context, it is given while recounting the provision of manna in the wilderness — when no other form of food was available, God provided bread from heaven for His people. This marvelous provision is what Jesus points in rebuking the devil. The Puritan Thomas Manton shows the significant connection of the two contexts as he expounds Matthew 4.
“In the place quoted, Moses speaks of manna, and shows how God gave His people manna from heaven, to teach them that though bread be the ordinary means of sustaining man, yet God can feed them by other means, which He is pleased to make use of for that purpose. His bare word, or nothing; all comes from His divine power and virtue, whatever He is pleased to give for the sustenation of man, ordinary or extraordinary. The tempter had said that either He must die for hunger, or turn stones into bread. Christ shows that there is a middle between both these extremes. There are other ways which the wisdom of God has found out or appointed by His word, or decreed to such an end, and makes use of in the course of His providence. And the instance is filthy chosen; for He that provided forty years for a huge multitude in the desert, he will not be lacking to His own Son, who had now fasted but forty days.” [I:272]