But He answered, “It is written:
Man must not live on bread alone
but on every word that comes
from the mouth of God.”
– Matthew 4:4 (HCSB)
Jesus was quoting what we now call Deuteronomy 8:3, the words of Moses to the Israelites: “Yes, he humbled you by letting you go hungry and then feeding you with manna, a food previously unknown to you and your ancestors. He did it to teach you that people do not live by bread alone; rather, we live by every word that comes from the mouth of the Lord.”
– Deuteronomy 8:3 (NLT)
When Moses spoke those words to the Israelites, there were not yet written Scriptures. The “every word that comes from the mouth of the LORD” came to the Israelites through prophets of God–Moses, Miriam, and later, others.
When we receive prophetic words today that are truly inspired by God’s Spirit, these are a vital part of the “every word that comes from the mouth of God” by which we must live, as Jesus affirmed.