The Wealth of Nations by Part 1 Chapter 11 Page 6

If it is not more, though the commodity may be brought to market, it can afford no rent to the landlord.

Whether the price is or is not more depends upon the demand.

There are some parts of the produce of land for which the demand must always be such as to afford a greater price than what is sufficient to bring them to market; and there are others for which it either may or may not be such as to afford this greater price. The former must always afford a rent to the landlord. The latter sometimes may, and sometimes may not, according to different circumstances.

Rent, it is to be observed, therefore, enters into the composition of the price of commodities in a different way from wages and profit. High or low wages and profit are the causes of high or low