Herein is the tragedy: that men doing outrage to their proper natures, even those called wise and good, lend themselves to perform the office of inferior and brutal ones. Hence come war and slavery in; and what else may not come in by this opening? But certainly there are modes by which a man may put bread into his mouth which will not prejudice him as a companion and neighbor.

– Henry David Thoreau, from “Monday,” A Week on the Concord and Merrimack Rivers (location 283 of 882)

Longer, with more context:

If, for instance, a man asserts the value of individual liberty over the merely political commonweal, his neighbor still tolerates him, that he who is living near him, sometimes even sustains him, but never the State. Its officer, as a living man, may have human virtues and a thought in his brain, but as the tool of an institution, a jailer or constable it may be, he is not a whit superior to his prison key or his staff. Herein is the tragedy: that men doing outrage to their proper natures, even those called wise and good, lend themselves to perform the office of inferior and brutal ones. Hence come war and slavery in; and what else may not come in by this opening? But certainly there are modes by which a man may put bread into his mouth which will not prejudice him as a companion and neighbor.

– Henry David Thoreau, from “Monday,” A Week on the Concord and Merrimack Rivers (location 283 of 882)