In history of human writings, various famous thermodynamics quotations have been repeated so much that they have gained a certain level of fame. These are shown below arranged in a loose order of precedence and by ranked order of commonality of occurrence:

Founding quotes

"Any method involving the notion of entropy, the very existence of which depends on the second law of thermodynamics, will doubtless seem to many far-fetched, and may repel beginners as obscure and difficult of comprehension."

— Willard Gibbs, Graphical Methods in the Thermodynamics of Fluids (1873) [1]

“The fascination of a growing science lies in the work of the pioneers at the very borderland of the unknown, but to reach this frontier one must pass over well traveled roads; of these one of the safest and surest is the broad highway of thermodynamics.”

— Gilbert Lewis and Merle Randall, Thermodynamics and the Free Energy of Chemical Substances (1923) [2]

“If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.”

— Sir Arthur Stanley Eddington, The Nature of the Physical World (1928) [3]

"A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability. Therefore the deep impression that classical thermodynamics made upon me. It is the only physical theory of universal content which I am convinced will never be overthrown, within the framework of applicability of its basic concepts."

— Albert Einstein, Autobiographical Notes (c. 1940s) [4]

“The concept of an independent system is a pure creation of the imagination. For no material system is or can ever be perfectly isolated from the rest of the world. Nevertheless it completes the mathematician’s ‘blank form of a universe’ without which his investigations are impossible. It enables him to introduce into his geometrical space, not only masses and configurations, but also physical structure and chemical composition. Just as Newton first conclusively showed that this is a world of masses, so Willard Gibbs first revealed it as a world of systems.”

— Lawrence Henderson, The Order of Nature: An Essay (1917), [5]

Infamous quotes

"Clausius and Darwin cannot both be right.”

— Roger Caillois, Coherences Aventureuses (1976), [6]

References
1. Gibbs, J. Willard. (1873). "Graphical Methods in the Thermodynamics of Fluids", Transactions of the Connecticut Academy, I. pp. 309-342, April-May.
2. (a) Lewis, Gilbert & Randall, Merle. (1923). Thermodynamics and the Free Energy of Chemical Substances, (pg. x). New York: McGraw-Hill Book Co., Inc.
(b) Cavazox-Gaither A.E. (2002). Chemically Speaking: A Dictionary of Quotations, (section: “Thermodynamics”, pg. 427-28). CRC Press.
3. Eddington, Arthur S. (1928). The Nature of the Physical World, (pg. 74). Cambridge: Cambridge University Press.
4. (a) Einstein, Albert. (author), Paul Arthur, Schilpp (editor). (1979). Autobiographical Notes. A Centennial Edition, (p. 31). Open Court Publishing Company.
(b) As quoted by Don Howard, John Stachel. Einstein: The Formative Years, 1879-1909 (Einstein Studies, vol. 8). Birkhäuser Boston. 2000. (p. 1).
5. (a) Henderson, Lawrence J. (1917). The Order of Nature: An Essay (pg. 126). Cambridge, Mass.: Harvard University Press.
(b) Bynum W.F. and Porter, Roy. (2005). Oxford Dictionary of Scientific Quotations, (pg. 275:6). Oxford: Oxford University Press.
6. (a) Caillois, Roger. (1976). Coherences Aventureuses. Paris: Gallimard.
(b) Thaxton, Charles B., Bradley, Walter L., Olsen, Roger L. (1992). The Mystery of Life’s Origin: Reassessing Current Theories, (ch. 7: “Thermodynamics of Living Systems”, ch. 8: “Thermodynamics and the Origin of Life”). Lewis and Stanley.
(c) Bushev, Michael. (1994). Synergetics: Chaos, Order, Self-organization, (pg. 130). World Scientific.