The Wealth of Nations by Part 1 Chapter 9 Page 26

it, as the ordinary rate of clear profit would be very small, so the usual market rate of interest which could be afforded out of it would be so low as to render it impossible for any but the very wealthiest people to live upon the interest of their money.

All people of small or middling fortunes would be obliged to superintend themselves the employment of their own stocks. It would be necessary that almost every man should be a man of business, or engage in some sort of trade. The province of Holland seems to be approaching near to this state. It is there unfashionable not to be a man of business. Necessity makes it usual for almost every man to be so, and custom everywhere regulates fashion. As it is ridiculous not to dress, so is it, in some measure, not to be employed, like other people. As a man of a civil profession