Which verse mentions "Man shall not live on bread alone, but on every word that comes from the mouth of God."? It is written: 'Man shall not live on bread alone, but on every word that comes from the mouth of God.'

Which verse mentions this?
It is in Deut 8:3, part of an extremely important and the last sermon Moses gave to the 2nd generation of Israelites while they were camping on the Plains of Moab before entering Canaan.  The main theme was reminding them of the importance to follow God's commandments so they would prosper in the promised land.  Otherwise they could end up like the 1st generation after Exodus whom God punished to die in the wilderness (except Caleb and Joshua).  Even God didn't allow Moses to enter Canaan.

The New Testament recorded Jesus quoting Deut 8:3 in response to the temptation of the devil while Jesus was fasting 40 days in the wilderness, similar to how the 1st generation was tested in the wilderness for 40 years.  But unlike the Israelites, Jesus succeeded.  Two passages recorded the quote:


Matt 4:4
Luke 4:4