To dig in the mellow soil-to dig moderately, for all pleasure should be taken sparingly-is a great thing. One gets strength out of the ground as often as one really touches it with a hoe. Antaeus (this is a classical article) was no doubt an agriculturist; and such a prize-fighter as Hercules couldn’t do any thing with him till he got him to lay down his spade, and quit the soil. It is not simply beets and potatoes and corn and string-beans that one raises in his well-hoed garden: it is the average of human life. There is life in the ground; it goes into the seeds; and it also, when it is stirred up, goes into the man who stirs it. The hot sun on his back as he bends to his shovel and hoe, or contemplatively rakes the warm and fragrant loam, is better than much medicine.
My Summer in a Garden, Charles Dudley Warner
Shoshin Ecological Farming and Gardening 