The Wealth of Nations by Part 2 Chapter 3 Page 25

different set of people, by labourers, manufacturers, and artificers, who reproduce with a profit the value of their annual consumption. His revenue, we shall suppose, is paid him in money. Had he spent the whole, the food, clothing, and lodging, which the whole could have purchased, would have been distributed among the former set of people. By saving a part of it, as that part is for the sake of the profit immediately employed as a capital either by himself or by some other person, the food, clothing, and lodging, which may be purchased with it, are necessarily reserved for the latter.

The consumption is the same, but the consumers are different.

By what a frugal man annually saves, he not only affords maintenance to an additional number of productive hands, for that or the ensuing