"The unwillingness of people to spend are a function of their chronic pessimism has been a major drag on the German economy."

http://www.nytimes.com/2006/07/11/business/worldbusiness/11cup.html

This quote accurate depicts why some countries remain poor since the people in that countries do not spend or invest in the money they spend. Anytime a person works and receives money for their services it means they are contributing to society and receiving a resource in the of form money which can be easily exchange for anything they may need or want. This is explicit reason why banks exist to make sure the resources that are sitting idle (money not being spent) are lent to the people or organization that needs money in loans and investments. Banks are the are agents which brings the borrowers with the savers. The capital markets exist to further the role in the economy.

For a economy to really thrive money needs to flow in the economy.