“The still sowe eats up all the draffe.”

Source: The Flame is Green (1971), Ch. 5 : Muerte De Boscaje
Context: “The world is a garden,” the old man said. “It is a farm, a plantation, a sheep-ranch. In the garden are the cities also; they too are a great part of the planting. Believe me, all these plantations are sowed with good seed. But the Enemy from the Beginning also sows the red blight: these are the charlocks, the tares, called zizania in the Vulgate. Do not be fooled as to what it is and who sowed it. Do not be fooled in the factory or the arsenal, in the ship-yard or the shop; do not be fooled on the bleak farms or in the crowded city, in the club or in the workers’ hall or in the drawing room. The wrong thing that is sowed is the red weed, the red blight. And the Enemy has done this.
"Or let us say that we have a green thing growing forever. Everything that is done is done by it. And on it we also have the red parasite crunching forever: and everything that is undone is undone by that. The parasite will present itself as a modern thing. It will call itself the Great Change. Less often, and warily, it will call itself the Great Renewal. But it can never be another thing than the Red Failure returned. It is a disease, it is a scarlet fever, a typhoid, a diphtheria; it is the Africa disease, it is the red leprosy, it is the crab-cancer. It is the death of the individual and of the corporate soul. And incidentally, but very often, it is also the death of the individual and of the corporate body. We are asked to swear fealty to the parasite disease which the enemy sowed from the beginning. I will not do it, and I hope that you will not."

Source: The 7 Habits of Highly Effective People

Letter XXVI
The Screwtape Letters (1942)

Saying published anonymously in The Dayspring, Vol. 10 (1881) by the Unitarian Sunday-School Society, and quoted in Life and Labor (1887) by Smiles; this is most often attributed to George Dana Boardman, at least as early as 1884, but also sometimes attributed to William Makepeace Thackeray as early as 1891, probably because in in Life and Labor Smiles adds a quote by Thackeray right after this one, to Charles Reade in 1903, and to William James as early as 1906, because it appears in his Principles of Psychology (1890).
Misattributed
Source: Happy Homes and the Hearts That Make Them

Reported in Phinneys' Calendar (1878), edited by Andrew Beers.

Possibly a misattribution, ascribed to Reade in Notes and Queries (9th Series) vol. 12, 17 October 1903. It appears (as an un-sourced quotation) in Life and Labor (1887) by Samuel Smiles and in the front of The Power of Womanhood by Ellice Hopkins (1899) htm http://www.gutenberg.org/files/13722/13722-h/13722-h..
Apparently a common saying in 19th century. It has been also attributed to an “old Chinese proverb”, Ralph Waldo Emerson (1803-1882), William Makepeace Thackeray (1811–1863), George Dana Boardman (1828-1903), Frances Elizabeth Caroline Willard (1839-1898), James Allen (1864-1912), Marcus Fabius Quintilianus http://en.wikipedia.org/wiki/Quintilian http://www.worldofquotes.com/author/Quintilian-(Marcus-Fabius-Quintilian)/1/index.html and William James.
No original source has ever been isolated. Its structure strongly reflects that of a ""classical Chinese"" set of aphorisms; and it may have been deliberately constructed in that form, by a non-Chinese, to imply an oriental (and, perhaps, far wiser) origin.
Finally, almost all of those who cite the complete piece:
::We sow a thought and reap an act;
::We sow an act and reap a habit;
::We sow a habit and reap a character;
::We sow a character and reap a destiny.
state that, in their view, it was written to expand an embellish the notion that was expressed at Proverbs XXIII:7 (""For as he thinketh in his heart, so is he"").
Attributed

Byrne, Robert. The 2,548 Wittiest Things Anybody Ever Said, page 372. http://books.google.com/books?id=odz2rZirMAkC&pg=PT372 Simon and Schuster, 2012. ISBN 145164891X
Attributed