3 And the tempter came and said to him, ‘If you are the Son of God, command these stones to become loaves of bread.’ 4 But he answered, ‘It is written, “Man shall not live by bread alone, but by every word (rhema) that comes from the mouth of God.”‘ Matthew 4:3-4 (ESV)
In Greek there are at least three terms that are all translated “word” (English is a less rich language in this case)
rhema (4487) – that which is or has been uttered by the living voice, thing spoken, word.
logos (3056) – of speech, word, what someone has said
graphe (1124) – a writing, a thing written, Scripture (usually referring to the Old Testastament)
This is an interesting verse in its specificity in pointing out that the man lives “by every word that comes from the mouth of God.” Many times we think of the word as Scripture but here it is including every word that comes from the mouth of God. Obviously, Scripture is a perfect source of the words of God but it is not the totality of the words (or every word) of God. In John 12:49, Jesus says “For I have not spoken on my own authority, but the Father who sent me has himself given me a commandment—what to say and what to speak.”
Not everything Jesus did or said was recorded, yet all were words of the Father. Sometimes the metaphor of spiritual bread is taken to be only the Scripture but this verse explicitly expands it to a much wider type of word of God. We need to discern the voice of God like Jesus, so as to gain sustenance and life from these words.
This verse clearly juxtaposes the tempter speaking and God speaking. Jesus discerns correctly the voice of the tempter and does not follow his suggestions and in opposition states that He lives on every word from the mouth of God (not limited to Scripture).
The immediate application is that in our lives, it is highly important to know who we are listening to, and discern and react well: to the tempter we do not join in his plan, and to the Father we savor and live off every word.