“A great stock, though with small profits, generally increases faster than a small stock with great profits. Money, says the proverb, makes money. When you have a little, it is often easier to get more. The great difficulty is to get that little.”

Source: The Principles of Political Economy and Taxation (1821) (Third Edition), Chapter I, On Value, p. 32

Listen, Little Man! (1948)
Context: You are Great, Little Man, when you are not small and petty. You are great when you carry on your trade lovingly, when you enjoy carving and building and painting and decorating and sowing, when you enjoy the blue sky and the deer and the dew and music and dancing, your growing children and the beautiful body of your woman or your man, when you learn to understand and think about life.

The Business of Life (1949)

Freeman (1948), p. 170
Variant: By desiring little, a poor man makes himself rich.

"Philadelphia Doctorate Course" #15 (1952).

Of Man's Progress in Virtue
Bartlett's Familiar Quotations, 10th ed. (1919)

The Crown of Wild Olive, lecture I: Work, sections 23-24 (1866).

you ask. "Well, I'll get more," he says. Just as at cricket, you get more runs. There's no use in the runs, but to get more of them than other people is the game. So all that great foul city of London there, — rattling, growling, smoking, stinking, — a ghastly heap of fermenting brickwork, pouring out poison at every pore, — you fancy it is a city of work? Not a street of it! It is a great city of play; very nasty play and very hard play, but still play.

The Crown of Wild Olive, lecture I: Work, sections 23-24 (1866)