Man shall not live by bread alone...
Thanks for your question.
In Matthew 4:4, Jesus says, But He answered and said, It is written, ‘Man shall not live by bread alone, but by every word that proceeds from the mouth of God. When you come across the statement, It is written, you need to go back to the original passage being quoted to understand what is being said. In this case it is Deuteronomy 8:3. This is in the context of Israel's 40 years in the wilderness and their trials at the hands of God just as Jesus was tempted for 40 days in the wilderness. It means that the most important things in life are not physical but rather spiritual. We do not truly live by bread but rather by the Word of God.
See also Jeremiah 15:16; Job 23:10-12; John 4:32-34; Matthew 6:25; 2 Corinthians 4:18
If you want to come to grips with what the Bible really teaches, why not take the free online Bible study course on our website, www.thisisyourbible.com? This course will give you a background in the major themes of the Bible from Genesis to Revelation. As with everything we offer, there is no cost to you other than your time and effort. You will also have a personal tutor to whom you may pose questions either from the course itself or those questions which come to you as you read the Bible.