Quality can refer to:
- A specific characteristic of an object (the qualities of ice - i.e. its properties)
- The achievement or excellence of an object (good quality ice - i.e. not of inferior grade)
- The essence of an object (the quality of ice - i.e. "iceness")
- The meaning of excellence itself
The first meaning is technical, the second practical, the third artistic, and the fourth metaphysical.
A - F 
- To understand the true quality of people, you must look into their minds, and examine their pursuits and aversions.
- Marcus Aurelius, Meditations, book 4, section 38 (trans. by Jeremy Collier).
- Things that have a common quality ever quickly seek their kind.
- Marcus Aurelius, Meditations, ix. 9.
- The quality of a man's mind can generally be judged by the size of his wastepaper basket.
- José Bergamín, La cabeza a pájaros (Head in the Clouds), p. 98, Madrid, Cruz y Raya (1934).
- So cheat your landlord if you can and must, but do not try to shortchange the Muse. It cannot be done. You can't fake quality any more than you can fake a good meal.
- William S. Burroughs, The Western Lands, ch. 2 (1987).
- The measure of your quality as a public person, as a citizen, is the gap between what you do and what you say.
- Ramsey Clark, International Herald Tribune (Paris, June 18, 1991).
- Uncontrolled variation is the enemy of quality.
- Attributed to Edward Deming (1980) in: Chang W. Kang, Paul H. Kvam (2012) Basic Statistical Tools for Improving Quality. p.19
- A demd, damp, moist, unpleasant body!
- Charles Dickens, Nicholas Nickelby, Chapter XXXIV.
- It is the quality of the moment, not the number of days, or events, or of actors, that imports.
- Ralph Waldo Emerson, speech, January 1842, at the Masonic Temple in Boston, repr. in The Dial (1843) and Nature, Addresses, and Lectures (1849).
- It's the quality of the ordinary, the straight, the square, that accounts for the great stability and success of our nation. It's a quality to be proud of. But it's a quality that many people seem to have neglected.
G - L 
- One cannot develop taste from what is of average quality but only from the very best.
- Johann Wolfgang von Goethe, Conversations with Eckermann (February 26, 1824).
- One shining quality lends a lustre to another, or hides some glaring defect.
- William Hazlitt, Complete Works, vol. 9, ed. P.P. Howe (1932). Characteristics, no. 162 (first published anonymously in 1823).
- Social improvement is attained more readily by a concern with the quality of results than with the purity of motives.
- Eric Hoffer, Reflections on the Human Condition, aph. 25 (1973).
- The quality of moral behaviour varies in inverse ratio to the number of human beings involved.
- Aldous Huxley, Grey Eminence, ch. 10 (1941).
- Hard as a piece of the nether millstone.
- Job. XLI. 24. reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 653.
M - R 
- Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted?
- Matthew. V. 13. reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 653.
- People of quality know everything without ever having learned anything.
- Molière, Les Précieuses Ridicules, sc. 9 (1659).
- Much of what passes for quality on British television is no more than a reflection of the narrow elite which controls it and has always thought that its tastes were synonymous with quality.
- Rupert Murdoch, Address, 1989, to the Edinburgh Television Festival. quoted in Guardian (London, Jan. 1, 1990).
- Admiration for a quality or an art can be so strong that it deters us from striving to possess it.
- Friedrich Nietzsche, Mixed Opinions and Maxims, aphorism 370, "The Danger in Admiration," (1879).
- A quality is something capable of being completely embodied. A law never can be embodied in its character as a law except by determining a habit. A quality is how something may or might have been. A law is how an endless future must continue to be.
- Charles Peirce, Collected Papers (lecture 3 of Lowell Lectures of 1903), vol. 1, para. 536, Harvard University Press (1934).
- Fine by defect, and delicately weak.
- Alexander Pope, Moral Essays (1731-35), Epistle II, line 43.
- That air and harmony of shape express,
Fine by degrees, and beautifully less.
- Matthew Prior, Henry and Emma, line 432. reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 653.
S - Z 
- Come, give us a taste of your quality.
- Innocence in genius, and candor in power, are both noble qualities.
- Anne Louise Germaine de Staël, Germany, Part II, Chapter VIII.
- To affect the quality of the day, that is the highest of arts. Every man is tasked to make his life, even in its details, worthy of the contemplation of his most elevated and critical hour.
- Henry David Thoreau, The Writings of Henry David Thoreau, vol. 2, p. 100, Houghton Mifflin (1906).
- Nothing endures but personal qualities.
- Walt Whitman, Leaves of Grass, Song of the Broad-Axe, Stanza 4.