But as I sat scrawling these silly figures on the brown paper, it began to dawn on me, to my great disgust, that I had left one chalk, and that a most exquisite and essential chalk, behind. I searched all my pockets, but I could not find any white chalk. Now, those who are acquainted with all the philosophy (nay, religion) which is typified in the art of drawing on brown paper, know that white is positive and essential. I cannot avoid remarking here upon a moral significance. One of the wise and awful truths which this brown-paper art reveals, is this, that white is a color. It is not a mere absence of color; it is a shining and affirmative thing, as fierce as red, as definite as black. When, so to speak, your pencil grows red-hot, it draws roses; when it grows white-hot, it draws stars. And one of the two or three defiant verities of the best religious morality, of real Christianity, for example, is exactly this same thing; the chief assertion of religious morality is that white is a color. Virtue is not the absence of vices or the avoidance of moral dangers; virtue is a vivid and separate thing, like pain or a particular smell. Mercy does not mean not being cruel, or sparing people revenge or punishment; it means a plain and positive thing like the sun, which one has either seen or not seen.This quote is from the essay "A Piece of Chalk" from an essay in TREMENDOUS TRIFLES. The original essay appeared in the DAILY NEWS, November 4, 1905, according to the ACS web site.
I don't know, this commercialization of his words just seems strange, although given the long history of this company (started in 1892, the year Chesterton won his Milton prize for the poem St. Francis Xavier on Apposition Day), I suppose it's slightly better than finding his words on a StuffMart ad.