Government, Aristotle says, should be by those people with enough time on their hands to pursue virtue. This is a far cry from the current U.S. drive towards campaign financing laws designed to make the political life available even to those without well-endowed fathers. It is also very different from the modern career politician who derives his wealth at the expense of the citizenry. Aristotle thinks rulers should be propertied and leisured, so, without other worries, they can invest their time in producing virtue. Laborers are too busy.
Book III -"But the citizen whom we are seeking to define is a citizen in the strictest sense, against whom no such exception can be taken, and his special characteristic is that he shares in the administration of justice, and in offices. He who has the power to take part in the deliberative or judicial administration of any state is said by us to be a citizens of that state; and, speaking generally, a state is a body of citizens sufficing for the purposes of life.
...For tyranny is a kind of monarchy which has in view the interest of the monarch only; oligarchy has in view the interest of the wealthy; democracy, of the needy: none of them the common good of all. Tyranny, as I was saying, is monarchy exercising the rule of a master over the political society; oligarchy is when men of property have the government in their hands; democracy, the opposite, when the indigent, and not the men of property, are the rulers."
Book VII
"The citizens must not lead the life of mechanics or tradesmen, for such a life is ignoble, and inimical to virtue. Neither must they be farmers, since leisure is necessary both for the development of virtue and the performance of political duties."
Source:
Aristotle Politics
Features on Democracy in Ancient Greece and the Rise of Democracy
Ancient Writers on Democracy