What are the purpose and thesis of Thoreau's essay "Walking"?

Henry David Thoreau was an advocate of all things nature, and this essay of his is no exception. Here, he champions a simple act that seems to have become a lost art in modern society:

"I have met with but one or two persons in the course of my life who understood the art of Walking, that is, of taking walks—who had a genius, so to speak, for sauntering" (Thoreau).

His point is that walking—not out of necessity, but true, obligation-free walking out in nature—is an essential part of humanity that has been lost. The constant rush and pressures of society inhibit this part of us, according to Thoreau:

"When sometimes I am reminded that the mechanics and shopkeepers stay in their shops not only all the forenoon, but all the afternoon too . . . as if the legs were made to sit upon, and not to stand or walk upon—I think that they deserve some credit for not having all committed suicide long ago" (Thoreau).

He also makes a point about mindfulness, namely that to truly enjoy walks out in the woods one must "shake off the village." His thesis can most suitably be summed up in this sentence:

"If you are ready to leave father and mother, and brother and sister, and wife and child and friends, and never see them again—if you have paid your debts, and made your will, and settled all your affairs, and are a free man; then you are ready for a walk" (Thoreau).