In the economy, there will be those who spend less than the revenue. At the same time, it has spent more than income, thus lending occurs by the financial markets as a medium between borrowers and those savings.
The economy will have to spend less than their income. While there are those who spend more than their income. The borrowing occurred The financial market intermediation between savers and borrowers.
In the economy would be users pay less income. While there are those who spend more than income. Thus borrowing occurs. By the market, financial intermediary between borrowers and savers.