"As to the rights of ownership - as to that principle which enables a man to say of any certain thing--"This is mine; it is my property"--where does that come from? If you look you will see that it comes from the right of the producer to the thing which he produces. What a man makes he can justly claim to be his. Whatever any individual, by the exercise of his powers, takes from the reservoirs of nature, molds into shapes fitted to satisfy human needs, that is his; to that a just and sacred right of property attaches. That is a right based on the right of the individual to improvement, the right to the enjoyment of his own powers, to the possession of the fruits of his exertions. That is a sacred right, to violate which is to violate the sacred command, "Thou shalt not steal." There is the right of ownership. Now that right, which gives by natural and Divine laws, the thing produced to him whose exertion has produced it, which gives to the man who builds a house the right to that house, to the man who raises a crop the right to that crop, to the man who raises a domestic animal a right to that domestic animal - How can that right attach to the reservoirs of nature? How can that right attach to the earth itself?
"We start out with these two principles, which I think are clear and self-evident: that which a man makes belongs to him and can by him be given or sold to anyone that he pleases But that which existed before man came upon the earth, that which was not produced by man, but which was created by God - That belongs equally to all men. As no man made the land, so no man can claim a right of ownership in the land. As God made the land, and as we know both from natural perception and from revealed religion, that God the Creator is no respecter of persons, that in His eyes all men are equal, so also do we know that He made this earth equally for all the human creatures that He has called to dwell upon it. We start out with this clear principle that as all men are here by the equal permission of the Creator, as they are all here under His laws equally requiring the use of land, as they are all here with equal right to live, so they are all here with equal right to the enjoyment of His bounty."
- Henry George, An Address Delivered on July 11, 1889, in Toomebridge, County Derry, Ireland
For a quick introduction to the basic premises behind Henry George's Single Tax, see - How Do We Divide The Fruits of Labor?
For additional information, read this great introductory article - The Only Economic Reform Worth Talking About