Matthew 4:4 says:
4Jesus answered him, "It is written [in the Scriptures], 'It is not just bread that keeps people alive. People's lives depend on what God says.'"Deuteronomy 8:3. (Easy-to-Read Version)
King James Version: 4But he answered and said, It is written, Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God.